**Exhibit 10.23****2004 Stock Incentive Plan**First, that the Title of the Plan is amended to read as follows:     “The Corporate Executive Board Company 2004 Stock Incentive Plan (as amended July 18,2005 and December 22, 2006).”Second, that the second sentence of Section 4 (Effective Date and Termination) of the Plan isamended to read as follows:“~~This~~The first amendment and restatement of the Plan was adopted by the Board ofDirectors of the Company as of July 18, 2005, which becameeffective~~and will becomeeffective~~ when ~~it is~~ approved by the Company’s stockholders on August 18, 2005.The second amendment and restatement of the plan was adopted by the Board of Directors ofthe Company on December 22, 2006.”Third, that Paragraphs 1 and 2 of Section 12 are amended to read as follows:“In the event that the number of shares of Common Stock of the Company shall be increased ordecreased through a reorganization, reclassification, combination of shares, stock split,reverse stock split, spin-off, dividend (other than regular, quarterly cash dividends), orotherwise in an equity restructuring transaction, as that term is defined in Statement ofFinancial Accounting Standards No. 123 (revised), then each share of Common Stock of theCompany which has been authorized for issuance under the Plan, whether such share is thencurrently subject to or may become subject to an Award under the Plan, as well as the pershare limits set forth in Section 5 of this Plan, ~~may~~shall be proportionatelyadjusted by the Administrator to reflect such increase or decrease, unless the Companyprovides otherwise under the terms of such transaction. The terms of any outstanding Award~~may~~ also shall be equitably adjusted by the Administrator as to price,and/or number of shares of Common Stock subject to such Award, and otherterms, to reflect the foregoing events.In the event there shall be any other change in the number or kind of outstanding shares ofCommon Stock of the Company, or any stock or other securities into which such Common Stockshall have been changed, or for which it shall have been exchanged, whether by reason of achange of control, other merger, consolidation or otherwise in circumstances that do notinvolve an equity restructuring transaction, as that term is defined in Statement ofFinancial Accounting Standards No. 123 (revised), then the Administrator shall, in itssole discretion, determine the appropriate adjustment, if any, to be effected. In addition,in the event of such change described in this paragraph, the Administrator may accelerate thetime or times at which any Award may be exercised and may provide for cancellation of suchaccelerated Awards that are not exercised within a time prescribed by the Administrator inits sole discretion. Notwithstanding anything to the contrary herein, any adjustment toOptions granted pursuant to this Plan intended to qualify as ISOs shall comply with therequirements, provisions and restrictions of the Code.Fourth, that item (vi) of Section 18(b) is amended to read as follows:     “toestablish the terms of~~determine whether, and the extent to which,~~ adjustments~~are required~~ pursuant to Section 12;”.
 

 
**2002 Non-Executive Stock Incentive Plan**First, that the first sentence of Section 4 is amended to read as follows:“This Plan was adopted by the Board of Directors of the Company as of March 6, 2002(the “Effective Date”), ~~and is~~was amended effective October 7, 2002 to permitgrants of Restricted Stock, and was further amended effective December 22, 2006 toaddress equity restructurings.Second, that paragraphs 1 and 2 of Section 9 are amended to read as follows:“In the event that the number of shares of Common Stock of the Company shall beincreased or decreased through reorganization, reclassification, combination ofshares, stock splits, reverse stock splits, spin-offs, or the payment of a stockdividend, (other than regular, quarterly cash dividends) or otherwise in an equityrestructuring transaction, as that term is defined in Statement of FinancialAccounting Standards No. 123 (revised), then each share of Common Stock of theCompany which has been authorized for issuance under the Plan, whether such share isthen currently subject to or may become subject to an Award under the Plan,~~may~~shall be proportionately adjusted to reflect such increase or decrease, unlessthe terms of the transaction provide otherwise. Outstanding Awards ~~may~~ alsoshall be ~~amended~~equitably adjusted as to price and otherterms, if necessary to reflect the foregoing events.”“In the event there shall be any other change in the number or kind of the outstandingshares of Common Stock of the Company, or any stock or other securities into whichsuch Common Stock shall have been changed, or for which it shall have been exchanged,whether by reason of merger, consolidation or otherwise in circumstances that donot involve an equity restructuring transaction, as that term is defined in Statementof Financial Accounting Standards No. 123 (revised), then the Administrator shall,in its sole discretion, determine the appropriate adjustment, if any, to be effected.In addition, in the event of such change described in this paragraph, theAdministrator may accelerate the time or times at which any Award may be exercised andmay provide for cancellation of such accelerated Awards which are not exercised withina time prescribed by the Administrator in its sole discretion.”Third, that item (g) of Section 12(b) is amended to read as follows:“to ~~determine whether, and the extent to which,~~establish the terms ofadjustments ~~are required~~ pursuant to Section 9 hereof; and”
 

 
**2001 Stock Option Plan**First, that Paragraphs 1 and 2 of Section 8 are amended to read as follows:“In the event that the number of shares of Common Stock of the Company shall beincreased or decreased through reorganization, reclassification, combination ofshares, stock splits, reverse stock splits, spin-offs, or the payment of a stockdividend, (other than regular, quarterly cash dividends) or otherwise in an equityrestructuring transaction, as that term is defined in Statement of FinancialAccounting Standards No. 123 (revised), then each share of Common Stock of theCompany which has been authorized for issuance under the Plan, whether such share isthen currently subject to or may become subject to an Option underthe Plan, ~~may~~shall be proportionately adjusted to reflect such increase or decrease, unlessthe terms of the transaction provide otherwise. Outstanding Options~~may~~ alsoshall be ~~amended~~equitably adjusted as to price and other terms ifnecessary to reflect the foregoing events.”“In the event there shall be any other change in the number or kind of the outstandingshares of Common Stock of the Company, or any stock or other securities into whichsuch Common Stock shall have been changed, or for which it shall have been exchanged,whether by reason of merger, consolidation or otherwise in circumstances that donot involve an equity restructuring transaction, as that term is defined in Statementof Financial Accounting Standards No. 123 (revised), then the Administrator shall,in its sole discretion, determine the appropriate adjustment, if any, to be effected.In addition, in the event of such change described in this paragraph, theAdministrator may accelerate the time or times at which any Option may be exercisedand may provide for cancellation of such accelerated Options which are not exercisedwithin a time prescribed by the Administrator in its sole discretion. Notwithstandinganything to the contrary herein, any adjustment to Options granted pursuant to thisPlan, particularly Options intending to qualify as ISOs, shall comply with therequirements, provisions and restrictions of the Code.”Second, that item (g) of Section 11 is amended to read as follows:“to~~determine whether, and the extent to which,~~establish the terms ofadjustments are required pursuant to Section 8 hereof; and”
 

 
**1999 Stock Option Plan**First, that Paragraphs 1 and 2 of Section 8 are amended to read as follows:“In the event that the number of shares of Common Stock of the Company shall beincreased or decreased through reorganization, reclassification, combination ofshares, stock splits, reverse stock splits, spin-offs, or the payment of a stockdividend, (other than regular, quarterly cash dividends) or otherwise in an equityrestructuring transaction, as that term is defined in Statement of FinancialAccounting Standards No. 123 (revised), then each share of Common Stock of theCompany which has been authorized for issuance under the Plan, whether such share isthen currently subject to or may become subject to an Option underthe Plan, ~~may~~shall be proportionately adjusted to reflect such increase or decrease, unlessthe terms of the transaction provide otherwise. Outstanding Options~~may~~ alsoshall be ~~amended~~equitably adjusted as to price and other terms ifnecessary to reflect the foregoing events.”“In the event there shall be any other change in the number or kind of the outstandingshares of Common Stock of the Company, or any stock or other securities into whichsuch Common Stock shall have been changed, or for which it shall have been exchanged,whether by reason of merger, consolidation or otherwise in circumstances that donot involve an equity restructuring transaction, as that term is defined in Statementof Financial Accounting Standards No. 123 (revised), then the Administrator shall,in its sole discretion, determine the appropriate adjustment, if any, to be effected.In addition, in the event of such change described in this paragraph, theAdministrator may accelerate the time or times at which any Option may be exercisedand may provide for cancellation of such accelerated Options which are not exercisedwithin a time prescribed by the Administrator in its sole discretion. Notwithstandinganything to the contrary herein, any adjustment to Options granted pursuant to thisPlan, particularly Options intending to qualify as ISOs, shall comply with therequirements, provisions and restrictions of the Code.”Second, that item (g) of Section 11 is amended to read as follows:“to~~determine whether, and the extent to which,~~establish the terms ofadjustments are required pursuant to Section 8 hereof; and”
 

 
**Employee Stock Purchase Plan**That Section 14 is amended to read as follows:**14.****Adjustments upon Changes in Securities****.****(a)**Subject to any required action by the stockholders of the Company, the number ofShares covered by each Right under the Plan that has not yet been exercised and thenumber of Shares that have been authorized for issuance under the Plan but have notyet been placed under a Right (collectively, the “Reserves”), as well as the price perShare covered by each Right under the Plan that has not yet been exercised, shall beproportionately adjusted for any increase or decrease in the number of issued Sharesresulting from a stock split or the payment of stock dividend (but only on the CommonStock) or any other increase or decrease in the number of Shares effected withoutreceipt of consideration by the Company, including any equity restructuringtransaction, as that term is defined in Statement of Financial Accounting StandardsNo. 123 (revised); provided, however, that conversion of any convertiblesecurities of the Company shall not be deemed to have been “ effected without receiptof consideration.” Such adjustment shall be made by the Committee, whosedetermination in that respect shall be final, binding and conclusive. Except asexpressly provided herein, no issue by the Company of shares of stock of any class, orsecurities convertible into shares of stock of any class, shall affect, and noadjustment by reason thereof shall be made with respect to, the number or price ofShares subject to a Right.**(b)**In the event of the proposed dissolution or liquidation of the Company, any andall Offerings shall terminate immediately prior to the consummation of such proposedaction, unless otherwise provided by the Committee. The Committee may, in theexercise of its sole discretion in such instances, declare that the Rights under thePlan shall terminate as of a date fixed by the Committee and give each Participant theright to exercise his or her Right. In the event of a proposed sale of all orsubstantially all of the assets of the Company, or the merger or consolidation of theCompany with or into another corporation or a parent or subsidiary of such successorcorporation when the Company is not the surviving corporation, or a reverse merger inwhich the Company is the surviving corporation but the Shares outstanding immediatelypreceding the merger are converted by virtue of the merger into other property,whether in the form of securities, cash or otherwise, in circumstances that do notinvolve an equity restructuring transaction, as that term is defined in Statement ofFinancial Accounting Standards No. 123 (revised), any and all Offerings shallterminate immediately prior to the consummation of such proposed action, unlessotherwise provided by the Committee. The Committee may, in the exercise of its solediscretion in such instances, and in lieu of assumption or substitution of the Rights,provide that each Participant shall have the right to exercise his or her Right. Ifthe Committee makes a Right exercisable in lieu of assumption or substitution in theevent of a merger or sale of assets, the Committee shall notify the Participant thatthe Right shall be fully exercisable for a period of twenty (20) days from the date ofsuch notice (or such other period of time as the Committee shall determine), and theRight shall terminate upon the expiration of such period.**(c)**The Committee shall~~may, if it so determines in the exercise of its solediscretion,~~ also make provision for adjusting the Reserves, as well as the price perShare covered by each outstanding Right, in the event that the Company effects one ormore reorganizations, recapitalizations, rights offering, or other increases orreductions of outstanding Shares in an equity restructuring transaction, as thatterm is defined in Statement of Financial Accounting Standards No. 123 (revised),and the Committee may, if it so determines in the exercise of its sole discretion,also make provision for adjusting the Reserves, as well as the price per Share coveredby each outstanding Right in the event of the Company being consolidated with ormerged into any other corporation.

 
**Directors’ Stock Plan**First, that item (d) of Section 7 is amended to read as follows:“to~~determine whether, and the extent to which,~~establish the terms ofadjustments ~~are~~ required pursuant to Section 9 hereof; and”Second, that Paragraph 1 of Section 9 is amended to read as follows:“If the outstanding securities of the class then subject to this Plan are increased,decreased or exchanged for or converted into cash, property or a different number orkind of shares or securities, or if cash, property or shares or securities aredistributed in respect of such outstanding securities, in either case as a result of areorganization, reclassification, dividend (other than a regular, quarterly cashdividend or an issuance of the class of securities then subject to this Plan as partof a public or private offering thereof) or other distribution, stock split, reversestock split, spin-off or the like in an equity restructuring transaction, as thatterm is defined in Statement of Financial Accounting Standards No. 123 (revised),or if substantially all of the property and assets of the Company are sold, then,~~unless the terms of such transaction shall~~~~provide otherwise,~~ the maximum number andtype of shares or other securities that may be issued under this Plan shall beappropriately adjusted. The Committee shall determine, in its sole discretion, theappropriate adjustment, ~~if any,~~ to be effected pursuant to the immediately precedingsentence. In addition, in connection with any such changes in the class of securitiesthen subject to this Plan, the Committee ~~may~~shall make appropriate andproportionate adjustments in the number and type of shares or other securities or cashor other property that may be acquired pursuant to Options and Stock Grantstheretofore awarded under this Plan and the exercise price of such Options or price,if any, of such Stock Grants.”