Looking for a board game like Arkham Horror?

I'm looking for a board game that resembles the coop play of Arkham Horror. I know there are a lot of games where it's 3 against one or so on and that's really not what I'm looking for. I want the board game to have it's on AI of sorts or allows for things to happen while the players try to work together to beat the game. I've heard of Defenders of the Realm and LOTR which are similar, but they didn't have the thematic or the feel I was looking for. Does anyone know of any other games like Arkham?