<PAGE>   1
                                                                    Exhibit 10.8




                               PENTON MEDIA, INC.

                           SENIOR EXECUTIVE BONUS PLAN

         1. PURPOSE. The purpose of the Senior Executive Bonus Plan (the "Plan")
is to attract and retain key executives for Penton Media, Inc., a Delaware
corporation (the "Company"), and its Subsidiaries and to provide such persons
with incentives for superior performance. Incentive Bonus payments made under
the Plan are intended to constitute qualified "performance-based compensation"
for purposes of Section 162(m) of the Code, and Section 1.162-27 of the
Regulations, and the Plan shall be construed consistently with such intention.

         2. DEFINITIONS. As used in this Plan,

                  "BOARD" means the Board of Directors of the Company.

                  "CODE" means the Internal Revenue Code of 1986, as amended
                  from time to time.

                  "COMMITTEE" means the Compensation Committee of the Board or
                  any other committee appointed by the Board to administer the
                  Plan; provided, however, that in any event the Committee shall
                  be comprised of not less than two directors of the Company,
                  each of whom shall qualify as an "outside director" for
                  purposes of Section 162(m) of the Code and Section
                  1.162-27(e)(3) of the Regulations.

                  "COMMON STOCK" means (i) shares of the common stock, par value
                  $.01, of the Company and (ii) any security into which Common
                  Stock may be converted by reason of any corporate capital
                  transaction.

                  "ELIGIBLE EXECUTIVE" means the Company's Chief Executive
                  Officer and each other executive officer of the Company that
                  the Committee determines is, or is likely to become, a
                  "covered employee" of the Company within the meaning of
                  Section 162(m) of the Code and Section 1.162-27(c)(2) of the
                  Regulations.

                  "INCENTIVE BONUS" shall mean, for each Eligible Executive, a
                  bonus opportunity amount determined by the Committee pursuant
                  to Section 5 below.

                  "MANAGEMENT OBJECTIVES" means the achievement of a performance
                  objective or objectives established pursuant to this Plan for
                  Eligible Executives. Management Objectives may be described in
                  terms of Company-wide objectives or objectives that are
                  related to the performance of the individual Eligible


                                       1
<PAGE>   2
                  Executive or of the Subsidiary, division, department or
                  function within the Company or Subsidiary in which the
                  Eligible Executive is employed. The Management Objectives
                  shall be limited to specified levels of or growth in:

                           (i)      return on invested capital;

                           (ii)     earnings per share;

                           (iii)    net earnings;

                           (iv)     operating profit;

                           (v)      pre-tax profit;

                           (vi)     after-tax cash flow per share;

                           (vii)    business unit contribution profit;

                           (viii)   earnings before interest expense, income tax
                                    expense, depreciation and amortization;

                           (ix)     total shareholder return (including relative
                                    to an index);

                           (x)      return on assets;

                           (xi)     return on equity;

                           (xii)    sales growth; and/or

                           (xiii)   productivity improvement.

                  "REGULATIONS" mean the Treasury Regulations promulgated under
                  the Code, as amended from time to time.

                  "SUBSIDIARY" means a corporation, partnership, joint venture,
                  unincorporated association or other entity in which the
                  Company has a direct or indirect ownership or other equity
                  interest.

         3. ADMINISTRATION OF THE PLAN. The Plan shall be administered by the
Committee, which shall have full power and authority to construe, interpret and
administer the Plan and shall have the exclusive right to establish Management
Objectives and the amount of Incentive Bonus payable to each Eligible Executive
upon the achievement of the specified Management Objectives.

         4. ELIGIBILITY. Eligibility under this Plan is limited to Eligible
Executives designated by the Committee in its sole and absolute discretion.

         5. AWARDS.

                  (a) Not later than the 90th day of each fiscal year of the
         Company, the Committee shall establish the Management Objectives for
         each Eligible Executive and the amount of Incentive Bonus payable (or
         formula for determining such amount) upon full achievement of the
         specified Management Objectives. The Committee may further specify in
         respect of the specified Management Objectives a minimum acceptable
         level of achievement below which no Incentive Bonus payment will be
         made and shall set forth a formula for determining the amount of any
         payment to be made if performance is at or above the minimum acceptable
         level but falls short of full achievement of the specified Management
         Objectives. The Committee may not modify any terms of awards


                                       2
<PAGE>   3
         established pursuant to this section, except to the extent that after
         such modification the Incentive Bonus would continue to constitute
         qualified "performance-based compensation" for purposes of Section
         162(m) of the Code.

                  (b) The Committee retains the discretion to reduce the amount
         of any Incentive Bonus that would be otherwise payable to an Eligible
         Executive (including a reduction in such amount to zero).

                  (c) Notwithstanding any other provision of the Plan to the
         contrary, in no event shall the Incentive Bonus paid to an Eligible
         Executive under the Plan for a year exceed $2,000,000.

         6. COMMITTEE CERTIFICATION. As soon as reasonably practicable after the
end of each fiscal year of the Company, the Committee shall determine whether
the Management Objective has been achieved and the amount of the Incentive Bonus
to be paid to each Eligible Executive for such fiscal year and shall certify
such determinations in writing. The Committee at such time shall further
specify, at its discretion, whether the amount of Incentive Bonus shall be paid
in cash, shares of Common Stock or a combination thereof. To the extent an
Incentive Bonus is paid in shares of Common Stock, the number of shares of
Common Stock shall be based on the closing price of Common Stock on the New York
Stock Exchange on the date of Committee certification. The Company shall not be
required to issue any fractional shares of Common Stock pursuant to this Plan,
and any fractional shares of Common Stock shall be settled in cash.

         7. PAYMENT OF INCENTIVE BONUSES. Subject to a valid election made by an
Eligible Executive with respect to the deferral of all or a portion of his or
her Incentive Bonus, including any such deferral into the Company's Management
Stock Purchase Plan, Incentive Bonuses shall be paid within 30 days after
written certification pursuant to Section 6.

         8. NO RIGHT TO BONUS OR CONTINUED EMPLOYMENT. Neither the establishment
of the Plan, the provision for or payment of any amounts hereunder nor any
action of the Company, the Board or the Committee with respect to the Plan shall
be held or construed to confer upon any person (a) any legal right to receive,
or any interest in, an Incentive Bonus or any other benefit under the Plan or
(b) any legal right to continue to serve as an officer or employee of the
Company or any Subsidiary of the Company.

         9. WITHHOLDING. The Company shall have the right to withhold, or
require an Eligible Executive to remit to the Company, an amount sufficient to
satisfy any applicable federal, state, local or foreign withholding tax
requirements imposed with respect to the payment of any Incentive Bonus.

         10. NONTRANSFERABILITY. Except as expressly provided by the Committee,
the rights and benefits under the Plan shall not be transferable or assignable
other than by will or the laws of descent and distribution.



                                       3
<PAGE>   4
         11. EFFECTIVE DATE. Subject to its approval by the shareholders, this
Plan shall become effective for bonuses earned in years beginning with the year
2000 and shall remain effective until the fifth anniversary of the date of such
approval, subject to any further shareholder approvals (or reapprovals) mandated
for performance-based compensation under Section 162(m) of the Code, and subject
to the right of the Board to terminate the Plan, on a prospective basis only, at
any time.



                                       4