Minicon 26 was held 29–31 March 1991 at the Radisson Hotel South (Bloomington). Guests of honor were George Alec Effinger (author), David Cherry (artist), Al Kuhfeld, Ph.D. (science), Suzanne V. Tompkins and Jerry Kaufman (fans), and Jon Singer (lunch). We don't have good records of the membership, but it likely totaled around 2500. The executive committee was Kay Drache, Karen Cooper, Karen Johnson, Lynn Litterer, and Polly Jo Peterson.
Here is the program book in PDF (95 MB), or the same, but lower quality and a much smaller download (4 MB).
And here are individual page images used to generate each of the above PDFs:
The Minicon 26 Program Book was published with the statement, "Copyright © by Minnesota Science Fiction Society. [...] All rights reserved under various and sundry agreements and conventions. [...] No maps, illustrations, or other portions of this book may be reproduced in any form with guilt feelings (except where expressly copyrighted, which require permission of the artist/writer)." The earlier stuff notwithstanding, that last bit seems to be a declaration of putting most of the book into the public domain. Let it be so. The expressly copyrighted things are covered here:
Components of the Minicon 26 Program Book by Fred A Levy Haskell (photo), Jeff Schalles (text), and Stu Shiffman (art) are licensed under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License.
Advertisements are copyrighted if so marked.
For somewhat higher video quality, you can also download all of the files needed to make yourself a copy of the DVD that the above file was extracted from.
Here's a video including images of some of the button badges used in this Minicon era.
The WWW had been invented by Minicon 26, but no web servers were live on the public Internet yet, so we're sure it didn't have a web site.
Here is a piece, mirrored from Gabe Helou, describing some public discussion after Minicon 25 (and hence related to planning Minicon 26).