FIRST SUPPLEMENTAL INDENTURE

Exhibit 10.2

FIRST SUPPLEMENTAL INDENTURE

FIRST SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), entered into as of June 16, 2005, among Advanstar Communications Inc., a New York corporation (the “Company”), the guarantors party hereto (the “Guarantors”) and Wells Fargo Bank, N.A. (successor by merger to Wells Fargo Bank Minnesota, N.A.), as trustee (the “Trustee”).

RECITALS

WHEREAS, the Company, the Guarantors party thereto and the Trustee entered into the Indenture, dated as of August 18, 2003 (the “Indenture”), relating to the Company’s Second Priority Senior Secured Floating Rate Notes due 2008 (the “Floating Rate Notes”) and 10 3/4% Second Priority Senior Secured Notes due 2010;

WHEREAS, the Company and the Guarantors propose certain amendments to the Indenture (the “Proposed Amendments”) with respect to the Floating Rate Notes only, which Proposed Amendments must be approved with the written consent of the holders (the “Holders”) of a majority of the outstanding aggregate principal amount of the Floating Rate Notes;

WHEREAS, the Company and the Guarantors also propose certain additional amendments to the Indenture (the “Additional Amendments” and together with the Proposed Amendments, the “Amendments”) with respect to the Floating Rate Notes only, which Additional Amendments must be approved with the written consent of the Holders of at least two-thirds of the outstanding aggregate principal amount of the Floating Rate Notes;

WHEREAS, the Company has made an offer to purchase the Floating Rate Notes and solicited the consents of the Holders of the Floating Rate Notes to the Amendments pursuant to the Offer to Purchase and Consent Solicitation Statement dated May 31, 2005 (the “Offer and Solicitation”), each upon the terms and subject to the conditions set forth therein;

WHEREAS, pursuant to the Offer and Solicitation, Company has received the valid consents of the Holders of at least a majority in outstanding aggregate principal amount of the Floating Rate Notes consenting to the substance of the Proposed Amendments set forth in this Supplemental Indenture;

WHEREAS, pursuant to the Offer and Solicitation, the Company has received the valid consents of the Holders of at least two-thirds in outstanding aggregate principal amount of the Floating Rate Notes consenting to the substance of the Additional Amendments set forth in this Supplemental Indenture;

WHEREAS, all conditions and requirements necessary to make this Supplemental Indenture a valid, binding, and legal instrument in accordance with the terms of the Indenture have been performed and fulfilled and the execution and delivery hereof have been in all respects duly authorized; and

WHEREAS, pursuant to Section 9.06 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture.

NOW, THEREFORE, in consideration of the premises herein contained and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, it is mutually covenanted and agreed as follows:

Section 1.  Defined Terms.  Capitalized terms used herein and not otherwise defined herein are used as defined in the Indenture.

Section 2.  Proposed Amendments to Indenture.  Effective as of the Amendment Effective Date for the Proposed Amendments (as defined below):

(a)           The following Sections of the Indenture shall no longer apply with respect to the Floating Rate Notes and the corresponding provisions in the Floating Rate Notes shall be deemed to be deleted in their entirety and replaced with the phrase “Intentionally Omitted”:

(b)           Section 5.01 of the Indenture captioned “Merger, Consolidation, or Sale of Assets” is hereby amended by rendering each of clause (c), clause (d) and the last sentence of Section 5.01 inapplicable with respect to the Floating Rate Notes.

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(c)           Section 6.01 of the Indenture captioned “Events of Default” is hereby amended by rendering each of clauses (d), (e), (f), (g), (j) and (k) inapplicable with respect to the Floating Rate Notes.

(d)           Any definitions used exclusively in the provisions of the Indenture which no longer apply to the Floating Rate Notes pursuant to Paragraphs (a) through (c) of this Section 2 are hereby deleted in their entirety from the Floating Rate Notes and in the Indenture shall no longer apply with respect to the Floating Rate Notes and all references to paragraphs, sections, articles or other terms or provisions of the Indenture which no longer apply to the Floating Rate Notes pursuant to Paragraphs (a) through (c) of this Section 2 above are hereby deleted in their entirety in the Floating Rate Notes and in the Indenture shall no longer apply to the Floating Rate Notes.

Section 3.  Additional Amendments to the Indenture. Effective as of the Amendment Effective Date for the Additional Amendments (as defined below):

(a)           The following Sections of the Indenture shall no longer apply with respect to the Floating Rate Notes and the corresponding provisions in the Floating Rate Notes shall be deemed to be deleted in their entirety and replaced with the phrase “Intentionally Omitted”:

(b) Any definitions used exclusively in the provisions of the Indenture which no longer apply to the Floating Rate Notes pursuant to this Paragraph (a) of this Section 3 are hereby deleted in their entirety from the Floating Rate Notes and in the Indenture shall no longer apply to the Floating Rate Notes, and all references to paragraphs, sections, articles or other terms or provisions of the Indenture which no longer apply to the Floating Rate Notes pursuant to Paragraphs (a) of this Section 3 above are hereby deleted in their entirety in the Floating Rate Notes and in the Indenture shall no longer apply to the Floating Rate Notes.

(c)           The Second Priority Liens are hereby released in their entirety with respect to the Floating Rate Notes.

The Trustee will instruct the Collateral Agent to execute and deliver and the Collateral Agent will promptly execute and deliver, such instruments effectuating or confirming such release of the Second Priority Liens which will have the effect solely of releasing such Second Priority Liens as to the Collateral described therein, on customary terms and without any recourse, representation, warranty or liability whatsoever.

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Section 4.   Indenture Ratified.  Except as hereby otherwise expressly provided, the Indenture is in all respects ratified and confirmed, and all the terms, provisions and conditions thereof shall be and remain in full force and effect.

Section 5.  Counterparts.  This Supplemental Indenture may be signed in various counterparts which together will constitute one and the same instrument.

Section 6.  Supplemental Indenture Is a Supplement To Indenture.  This Supplemental Indenture is an amendment supplemental to the Indenture and this Supplemental Indenture will henceforth be read together.

Section 7.  Governing Law.  This Supplemental Indenture shall be governed by and construed in accordance with the laws of the State of New York.

Section 8.  References to Supplemental Indenture.  Any and all notices, requests, certificates and other instruments executed and delivered after the execution and delivery of this Supplemental Indenture may refer to the Indenture without making specific reference to this Supplemental Indenture, but nevertheless all such references to the Indenture shall include this Supplemental Indenture unless the context otherwise requires.

Section 9.  Effect of this Supplemental Indenture.  From and after the Amendment Effective Date, the Indenture shall be deemed to be modified as herein provided but except as modified hereby, the Indenture shall continue in full force and effect. The Indenture as modified hereby shall be read taken and construed as one and the same instrument.

Section 10.  Severability.  In the event that any provisions of this Supplemental Indenture shall be invalid, illegal or unenforceable, the validity, legality and enforceability of the remaining provisions shall not in any way be affected or impaired thereby.

Section 11.  Trust Indenture Act.  If any provisions hereof limit, qualify or conflict with any provisions of the Trust Indenture Act of 1939 required under the Trust Indenture Act of 1939 to be a part of and govern this Supplemental Indenture, the provisions of the Trust Indenture Act of 1939 shall control. If any provision hereof modifies or excludes any provision of the Trust Indenture Act of 1939 that pursuant to the Trust Indenture Act of 1939 may be so modified or excluded, the provisions of the Trust Indenture Act of 1939 as modified or excluded hereby shall apply.

Section 12.  Trustee Makes No Representation.  The Trustee makes no representation as to the validity or adequacy of this Supplemental Indenture or the recitals contained herein.

Section 13.  Effect of Headings.  The section headings herein are for convenience only and shall not affect the construction thereof.

Section 14.  Effectiveness.  This Supplemental Indenture shall become effective upon execution by the Company, the Guarantors and the Trustee. As used herein, the “Amendment Effective Date” shall mean (i) with respect to Proposed Amendments, the date that the Company delivers written notice to the Trustee that consents have been received from Holders of at least a majority of the then outstanding aggregate principal amount of Floating Rate Notes and the

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related Notes have been accepted for purchase in the Offer and Solicitation and (ii) with respect to the Additional Amendments, the date that the Company delivers written notice to the Trustee that consents have been received from Holders of at least two-thirds of the then outstanding aggregate principal amount of the Floating Rate Notes and the related Notes have been accepted for purchase in the Offer and Solicitation.

[Signature Page Follows]

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IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed as of the date first above written.