Second Life
I mused about concerts in Second Life and it looks like my arch-nemesis Jonathan Coulton beat me to it. He's going to be playing on the 14th at 8pm EST at Menorca (I think). I'm gonna try and be there.
I went out there to take a few snaps of the venue as my alter-ego "Brad Susenko":
Looks pretty swanky. I've always wanted to play in half a dome.
Here's the view from the stage.
Various clickable posters around. Here's one of a Creative Commons license.
And here's one of the Creative Commons front page.
Very neat. I still need a better computer or video card to run this thing on, but I'll be interested to see how well the audio works.