Good 2 player games?

[EventHorizon]

I'm looking for some good games that you can play with a friend or two, by passing around your iDevice.
-Please don't list online multiplayer games, even if they can connect to eachother without wifi.
-please don't list games that would be awkward to play 2-player on a smaller iDevice, if you do, say iPad only. (a hockey game)

The only one i'm aware of right now is Pocket Tanks, so this is really a field of games im unaware of.