Hey guys. I have a group at my high schoo last period, and in the room we have a gamecube with 4 controllers. So far we have a pretty decent collection of games, and we're in the market for more. Do you guys have any suggestions? Here's what we have: Super Smash Brothers Melee Mario Kart Double Dash Goldeneye: Rogue Agent 007: Nightfire Timesplitters: Future Perfect F-Zero GX Splinter Cell Chaos Theory SSX 3 Red Faction 2 Tony Hawk's Underground Serious Sam: The Next Encounter XIII

Mario Party? 

Mario Power Tennis and Super Monkey Ball

Rogue Agent as a decent multiplayer game? I thought the map design in that game was god awful and the only saving grace was the traps, but okay. :P
 
Melee is enough on its own, and Double Dash is pretty good too. As has already been suggested, Mario Power Tennis is also good, pretty much the same craziness as the other Mario "party" games (not referring to the actual mario party franchise lol). I'd also recommend Wario Ware, but not the Mario Party games. Mario Party kinda got old for me at 11ish when I realised the board game part was shit boring unless something happened like stealing a star from a friend.

Alright, I'll pick up a copy of Power Tennis and Wario Ware. any other suggestions?

JJ, my play time on that is around 40 hours. Keep in mind this is all at a school. We're getting plenty of mileage out of TS.

Mario Golf 
Pokemon Colloseum 
1080 Snowboarding 
Super Mario Striker or Sega Soccer Slam 
Soul Calibur II 
 
..... you lucky blighter, have fun.