Xbox Live Arcade has plenty of good two players games, the pool game, bomberman etc. I know that probably rules out 50% of games on the 360 but all suggestions appreciated. They're both top fun in 2 player.
The top Xbox split screen games for cooperative play—an extensive list of favorites with In split screen mode, two players can play together.
This page contains a list of co-op games for the Xbox 360. You'll Popular Co- Op Searches Tower Bloxx Deluxe - coop for 2 players, combat for 4 players.