UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  -------------

                                  SCHEDULE 13D
                                 (Rule 13d-101)

                    Under the Securities Exchange Act of 1934
                               (Amendment No. 4)*



                                 InfoSpace, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                    45678T201
--------------------------------------------------------------------------------
                                 (CUSIP Number)

                         Sandell Asset Management Corp.
                               40 West 57th Street
                                   26th Floor
                               New York, NY 10019
                   Attention: Richard Gashler, General Counsel
                                  212-603-5700

                                 With a Copy to:
                              Marc Weingarten, Esq.
                            Schulte Roth & Zabel LLP
                                919 Third Avenue
                               New York, NY 10019
                                  212-756-2000
--------------------------------------------------------------------------------
(Name, Address and Telephone Number of Person Authorized to Receive Notices and
                                 Communications)

                                 October 2, 2008
                               -------------------
             (Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
schedule because of ss.ss. 240 13d-1(e), 240 13d-1(f) or 240 13d-1(g), check the
following box [ ].

Note: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 13d-7 for other parties
to whom copies are to be sent.

                          (Continued on following pages)
                               (Page 1 of 9 Pages)

--------------------
* The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page. The information required on the
remainder of this cover page shall not be deemed to be "filed" for the purpose
of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise
subject to the liabilities of that section of the Act but shall be subject to
all other provisions of the Act (however, see the Notes).





----------------------------                        ----------------------------
CUSIP No.  45678T201            SCHEDULE 13D        Page 2 of 9 Pages
----------------------------                        ----------------------------

------------- -----------------------------------------------------------------
     1        NAME OF REPORTING PERSON

              Castlerigg Master Investments Ltd.
------------- -----------------------------------------------------------------
     2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X|  (b) |_|
------------- -----------------------------------------------------------------
     3        SEC USE ONLY
------------- -----------------------------------------------------------------
     4        SOURCE OF FUNDS

              WC
------------- -----------------------------------------------------------------
     5        CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
              TO ITEMS 2(d) or 2(e)     |_|
------------- -----------------------------------------------------------------
     6        CITIZENSHIP OR PLACE OF ORGANIZATION

              British Virgin Islands
------------- -----------------------------------------------------------------
 NUMBER OF    7           SOLE VOTING POWER

   SHARES                 0
              ----------- -----------------------------------------------------
BENEFICIALLY  8           SHARED VOTING POWER

   OWNED                  2,771,204
              ----------- -----------------------------------------------------
  BY EACH     9           SOLE DISPOSITIVE POWER

 REPORTING                0
              ----------- -----------------------------------------------------
  PERSON      10          SHARED DISPOSITIVE POWER

   WITH                   2,771,204
------------- ----------- -----------------------------------------------------
     11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

              2,771,204
------------- -----------------------------------------------------------------
     12       CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
              SHARES |_|
------------- -----------------------------------------------------------------
     13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11

              8.4%
------------- -----------------------------------------------------------------
     14       TYPE OF REPORTING PERSON

              CO
------------- -----------------------------------------------------------------






----------------------------                        ----------------------------
CUSIP No.  45678T201            SCHEDULE 13D        Page 3 of 9 Pages
----------------------------                        ----------------------------

------------- -----------------------------------------------------------------
     1        NAME OF REPORTING PERSON

              Sandell Asset Management Corp.
------------- -----------------------------------------------------------------
     2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X|  (b) |_|
------------- -----------------------------------------------------------------
     3        SEC USE ONLY
------------- -----------------------------------------------------------------
     4        SOURCE OF FUNDS

              AF
------------- -----------------------------------------------------------------
     5        CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
              TO ITEMS 2(d) or 2(e)     |X|
------------- -----------------------------------------------------------------
     6        CITIZENSHIP OR PLACE OF ORGANIZATION

                                 Cayman Islands
------------- -----------------------------------------------------------------
 NUMBER OF    7           SOLE VOTING POWER

   SHARES                 0
              ----------- -----------------------------------------------------
BENEFICIALLY  8           SHARED VOTING POWER

   OWNED                  2,771,204
              ----------- -----------------------------------------------------
  BY EACH     9           SOLE DISPOSITIVE POWER

 REPORTING                0
              ----------- -----------------------------------------------------
  PERSON      10          SHARED DISPOSITIVE POWER

   WITH                   2,771,204
------------- ----------- -----------------------------------------------------
     11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

              2,771,204
------------- -----------------------------------------------------------------
     12       CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
              SHARES |_|
------------- -----------------------------------------------------------------
     13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11

              8.4%
------------- -----------------------------------------------------------------
     14       TYPE OF REPORTING PERSON

              CO
------------- -----------------------------------------------------------------






----------------------------                        ----------------------------
CUSIP No.  45678T201            SCHEDULE 13D        Page 4 of 9 Pages
----------------------------                        ----------------------------

------------- -----------------------------------------------------------------
     1        NAME OF REPORTING PERSON

              Castlerigg International Limited
------------- -----------------------------------------------------------------
     2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X|  (b) |_|
------------- -----------------------------------------------------------------
     3        SEC USE ONLY
------------- -----------------------------------------------------------------
     4        SOURCE OF FUNDS

              AF
------------- -----------------------------------------------------------------
     5        CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
              TO ITEMS 2(d) or 2(e)     |_|
------------- -----------------------------------------------------------------
     6        CITIZENSHIP OR PLACE OF ORGANIZATION

              British Virgin Islands
------------- -----------------------------------------------------------------
 NUMBER OF    7           SOLE VOTING POWER

   SHARES                 0
              ----------- -----------------------------------------------------
BENEFICIALLY  8           SHARED VOTING POWER

   OWNED                  2,771,204
              ----------- -----------------------------------------------------
  BY EACH     9           SOLE DISPOSITIVE POWER

 REPORTING                0
              ----------- -----------------------------------------------------
  PERSON      10          SHARED DISPOSITIVE POWER

   WITH                   2,771,204
------------- ----------- -----------------------------------------------------
     11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

              2,771,204
------------- -----------------------------------------------------------------
     12       CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
              SHARES |_|
------------- -----------------------------------------------------------------
     13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11

              8.4%
------------- -----------------------------------------------------------------
     14       TYPE OF REPORTING PERSON

              CO
------------- -----------------------------------------------------------------






----------------------------                        ----------------------------
CUSIP No.  45678T201            SCHEDULE 13D        Page 5 of 9 Pages
----------------------------                        ----------------------------

------------- -----------------------------------------------------------------
     1        NAME OF REPORTING PERSON

              Castlerigg International Holdings Limited
------------- -----------------------------------------------------------------
     2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X|  (b) |_|
------------- -----------------------------------------------------------------
     3        SEC USE ONLY
------------- -----------------------------------------------------------------
     4        SOURCE OF FUNDS

              AF
------------- -----------------------------------------------------------------
     5        CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
              TO ITEMS 2(d) or 2(e)     |_|
------------- -----------------------------------------------------------------
     6        CITIZENSHIP OR PLACE OF ORGANIZATION

              British Virgin Islands
------------- -----------------------------------------------------------------
 NUMBER OF    7           SOLE VOTING POWER

   SHARES                 0
              ----------- -----------------------------------------------------
BENEFICIALLY  8           SHARED VOTING POWER

   OWNED                  2,771,204
              ----------- -----------------------------------------------------
  BY EACH     9           SOLE DISPOSITIVE POWER

 REPORTING                0
              ----------- -----------------------------------------------------
  PERSON      10          SHARED DISPOSITIVE POWER

   WITH                   2,771,204
------------- ----------- -----------------------------------------------------
     11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

              2,771,204
------------- -----------------------------------------------------------------
     12       CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
              SHARES |_|
------------- -----------------------------------------------------------------
     13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11

              8.4%
------------- -----------------------------------------------------------------
     14       TYPE OF REPORTING PERSON

              CO
------------- -----------------------------------------------------------------






----------------------------                        ----------------------------
CUSIP No.  45678T201            SCHEDULE 13D        Page 6 of 9 Pages
----------------------------                        ----------------------------

------------- -----------------------------------------------------------------
     1        NAME OF REPORTING PERSON

              Thomas E. Sandell
------------- -----------------------------------------------------------------
     2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (a) |X|  (b) |_|
------------- -----------------------------------------------------------------
     3        SEC USE ONLY
------------- -----------------------------------------------------------------
     4        SOURCE OF FUNDS

              AF
------------- -----------------------------------------------------------------
     5        CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
              TO ITEMS 2(d) or 2(e)     |X|
------------- -----------------------------------------------------------------
     6        CITIZENSHIP OR PLACE OF ORGANIZATION

              Sweden
------------- -----------------------------------------------------------------
 NUMBER OF    7           SOLE VOTING POWER

   SHARES                 0
              ----------- -----------------------------------------------------
BENEFICIALLY  8           SHARED VOTING POWER

   OWNED                  2,771,204
              ----------- -----------------------------------------------------
  BY EACH     9           SOLE DISPOSITIVE POWER

 REPORTING                0
              ----------- -----------------------------------------------------
  PERSON      10          SHARED DISPOSITIVE POWER

   WITH                   2,771,204
------------- ----------- -----------------------------------------------------
     11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

              2,771,204
------------- -----------------------------------------------------------------
     12       CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
              SHARES |_|
------------- -----------------------------------------------------------------
     13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 11

              8.4%
------------- -----------------------------------------------------------------
     14       TYPE OF REPORTING PERSON

              IN
------------- -----------------------------------------------------------------





----------------------------                        ----------------------------
CUSIP No.  45678T201            SCHEDULE 13D        Page 7 of 9 Pages
----------------------------                        ----------------------------

This Amendment No. 4 is filed with respect to the shares of common stock, par
value $0.0001 per share (the "Common Stock"), of Infospace, Inc., a Delaware
corporation (the "Issuer"), beneficially owned by the Reporting Persons as of
October 2, 2008 and amends and supplements the Schedule 13D filed on March 12,
2007, as amended (collectively, the "Schedule 13D"). Except as set forth herein,
the Schedule 13D is unmodified.

Item 2.       IDENDITY AND BACKGROUN

Paragraph (a) of Item 2 is hereby amended by deleting Castlerigg Global Select
Fund, Limited, CGS, Ltd., and Castlerigg GS Holdings, Ltd. These entities are no
longer reporting persons for purposes of this Schedule 13D as a result of the
merger of CGS, Ltd. and Castlerigg Master Investments Ltd.

ITEM 4.       PURPOSE OF TRANSACTION

Item 4 of the Schedule 13D is hereby amended and supplemented by the addition of
the following paragraph immediately preceding the penultimate paragraph thereof:

        On October 2, 2008, Nick Graziano, a Managing Director of Sandell and a
member of the Board of Directors of the Issuer since his appointment in
connection with the April 26 Agreement in April, 2007, notified the Issuer that
he was resigning from the Board effective immediately. In his letter of
resignation, Mr. Graziano indicated that he was not resigning as the result of
any disagreement.  Rather, Mr. Graziano noted that both the Board and management
are very capable and have a clear strategy going forward that accurately
reflects the best interests of shareholders.  Mr. Graziano stated that the
restructuring efforts undertaken by the Board since his appointment are largely
complete, and accordingly that he felt this was an appropriate time for him to
resign.






----------------------------                        ----------------------------
CUSIP No.  45678T201            SCHEDULE 13D        Page 8 of 9 Pages
----------------------------                        ----------------------------

                                    Signature

     After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

     Dated: October 3, 2008

            CASTLERIGG MASTER INVESTMENTS LTD.
            By:  Sandell Asset Management Corp., as investment manager

            By: /s/ Thomas E. Sandell
                ---------------------
                    Thomas E. Sandell, Director
                    Chief Executive Officer


            SANDELL ASSET MANAGEMENT CORP.


            By: /s/ Thomas E. Sandell
                ---------------------
                    Thomas E. Sandell
                    Chief Executive Officer


            CASTLERIGG INTERNATIONAL LIMITED
            By:  Sandell Asset Management Corp., as investment manager

            By: /s/ Thomas E. Sandell
                ---------------------
                    Thomas E. Sandell
                    Chief Executive Officer


            CASTLERIGG INTERNATIONAL HOLDINGS LIMITED
            By:  Sandell Asset Management Corp., as investment manager

            By: /s/ Thomas E. Sandell
                ---------------------
                    Thomas E. Sandell
                    Chief Executive Officer


            /s/ Thomas E. Sandell
            ---------------------
            Thomas E. Sandell