I would strongly encourage bringing Rock Band. It's an awesome party game. Either the two musics clash a little bit, it's not like we have some sick giant sound system coming aside from the seasoned mix, or we turn down one to play the other. PLEASE PLEASE PLEASE bring Rock Band (3?). Hopefully you'd have Drums, 2 guitars and 3 mics. I can bring my USB stick with a ton of DLC if it would help. And I can bring Lips mics if we need to. If anyone has Mic stands, that is always an awesome addition.
You'll be surprised how you can get away with playing multiple musics in a space.
Is anyone focusing on other multiplayer games, like Chu Chu Rocket (and SF Rush 2049 for DC!), Warlords/Medieval Madness, Super Bomberman (TG vs SNES?) or whatever is 4 player?
My other comment is, don't be classic obsessed with the game titles. We all play them. It's a great opportunity for people to see any type of multiplayer, whether it's the latest NBA Jam on 360, or Video Olympics. Let's interact!