Need co-op board game suggestions
So I recently been really getting into board games with some of my friends. So far I've got and played Dominion, Dominion Intrigue, and Memoir 44 with them. I wanted to change things up from competitive games to a cooperative games. So does anybody have any coop board game suggestions?
My only request is that it needs to be simple and hopefully with some depth. Something that somebody can understand under a couple of turns and a good explanation from me (easy to learn, tough to master). My friends are not uber nerds so they will have very little patience with this stuff. Obviously Arkham Asylum will be off of the list! So far I was looking at Pandemic and Shadows Over Camelot. I would like a first hand experience with those games or any other games. Any help goodjers?
EDIT: Please keep suggestions under a 2 hours of play session. Thanks!