I went to the Extreme House one with JackLover and mz_. It was about an hour and 15 minutes long. It was very cool. T.J. went over the house in great detail, scene-by-scene. I can tell you that it was to have involved coffins, a bus, and an electric chair. There was going to be a code word or phrase that you could say if you wanted to leave because it was too intense. The phrase suggested by one of the designer's children was, "I'm a fluffy bunny." Lots of other members were there, too - Dr. Jimmy, Rob, Jim and Judy, so I'm sure someone could give you a more full run down. Or you can find me, JackLover, and mz_ one night and we'll tell you more about it. It's too much to type out.
Pictures from the event -
(Ignore the shoes; I just got off work and forgot to bring my non-work shoes)