Patrick von Wiegandt has the answer. His Honolulu based company, von Wiegandt Productions , travels the country recording presentations given at computer conventions. Electronics Entertainment Expo and DCI's Data Warehouse World. Von Wiegandt's company also records some non-computer conventions such as the recent Maui Writers Conference.
Conferences usually have several different sessions going on at the same time.
Honolulu resident Pamela Eden, who attended the Maui Writers Conference, bought 14 session tapes. She purchased tapes of sessions she missed, as well as those she attended. You can learn something new each time you listen to them. The 1996 Computer Game Developers' Conference in Santa Clara, California drew 4,000 participants to more than 235 seminars and discussions. They're all nuts.