Final Fantasy (the band.. or rather, the guy) was pretty neat. He plays his violin in a variety of ways, and he'll play a short loop, record and replay it with foot pedals, and then play new layers over that. Meanwhile, there's a shadow puppet show via overhead projector to go along with the music.
Here he's covering Bloc Party's "Modern Love" as he opens for them: (The drummer from Smoosh, the other opener, is helping out on this one, but she's not in frame.)
And here's Bloc Party. Clap your hands.
The ticket said "no camera or recorders", but flashes were going off all over the place:
This really made me appreciate the shutter-priority mode on my Fujifilm F30. Even though it doesn't have full manual, the shutter-priority is useful in a case like this when I want to artificially shorten the exposure beyond what I could do even with exposure compensation set to -2. (The backlighting effect wreaked havoc with the auto-exposure. :P)