Looking for an xbox game with?

Me and my friend were playing wager matches in black ops yesterday on splitscreen and we decided to team up. It was so much fun playing with just us to. I think that big teams are not as fun, and I am looking for a game that possibly has a game mode with 2 man teams, or just a small team tactical game. I am getting bored of COD and summer is coming and I need something to do. Another thing I want to sort of like MW2s spec ops except multiplayer, so you play with and against other people.