I have a bunch of games, and I want us all to play a fun game at once. If possible, try to stay away from shooters.
Also, you can include 360 games. I just put this in the Sony section because I play my PS3 a lot more than my 360.
EDIT: Offline games only
Little Big Planet, Rag doll Kung fu, Warhawk, All the smackdown games (6 player game), and basketball game (live, 2k series, and NBA 4-7 player games). These are the ones I know allow 4 or more players offline for multiplayer.