I think the craziest show I've seen was Terror playing at a house right down the street from me. They were playing in the living room and it was packed wall to wall. There were lots of people in other rooms of the house who couldn't get in. It was so hot in there that the windows and mirror in the corner were fogged up. The room had a high ceiling with two large beams going through the center, so naturally people (myself included) jumped off of them. It was total chaos in there. Unfortunately there are no videos of it.
1.31 Watain / Mayhem / Revenge
4.5 Antaeus / Demoncy / Volahn