Take a look at these games :)
Super Crate Box Together The original was awesome, but adding multiplayer make it even better !
Regular Human Basketball A team game, just look at a video ! Easily the funniest of the list
Eggnogg+ 2 players only, a lot of maps, swords, blood :)
aaannnnnnd, my first real PC game...
Lot of maps, weapons, skins, explosions and updates :)