Cooperative games on Wii

[Majin-Tenshinhan]

Resident Evil: Umbrella Chronicles is really fun, and it's getting a sequel this fall with Resident Evil: Darkside Chronicles.

Even though Punch-Out!! is a single-player game, I think it's really fun to play together and alternate with eachother.

Mario Strikers Charged is fun playing with a friend, you can challenge the story mode co-operatively.

And you can always play Subspace Emissary, the story mode of Super Smash Bros. Brawl.

Hope I helped.