Console(s): PS3, Xbox 360, Wii

One word: Zombies. We'll say it again: Zombies. Zombies. Zombies. This isn't a knock on Black Ops' campaign mode or anything, but the undead, multiplayer mayhem that the Zombies mode offers is one of the most addictive, and enjoyable co-op options on a seventh-gen console. Exercise moderation when playing this game. If you're not careful, you and your roommate could end up losing entire weeks of studying to CoD