When I come back home from college, I like to play games with my old friends, but more and more are we forced to play the same old games due to cruel, sadistic game publishers.
You should probably mention what consoles you have.
Borderlands series (2 players on couch, but up to four if you also use online friends)
Diablo 3 (up to four players, but one screen) ... works better than it sounds.
Divinity Original Sin (two players)
Child of Light (battle co-op)
The Lego games (fun, but aimed at a younger audience)
Some of the new Mario games have co-op.
Unfortunately, most people just play online now, so devs neglect couch co-op.
Hidden in Plain Sight is brilliant. Maximum 4 players I believe, stealth game where you have to deduce which of the sprites moving around is a real human, among a bunch of npcs. A couple different game modes, but assassin is the best, where there's one sniper and up to three assassins who go around killing people and you have to figure out why they are.