What are some of the best "bargain bin" games for 360? (Preferably multiplayer)

Hey there, I'm looking to buy into a few games that me and my friends may have missed out on. What are some fun multiplayer games we may have missed out on? We've only had our 360's about a year or so, so I'm sure we've missed a good 5 or 6 years worth of great games.

Things we've played (this list is tiny, I know.): Halo 3/Reach/ODST/4 Borderlands Castle Crashers BattleBlock Theater CoD

Basically, we're looking for great "bargain bin" games we can pickup for a few bucks and kill a week or two playing through together.