Good co-op games?

[GeneralSnake]

Splitscreen please..
I have done GoW 1&2, halo 3, RE5 was great co-op. Fable 2 is fun, but very limited splitscreen.
what are some fun games me and my friend can play locally, he has no xbox.

[Rovey Wade]

Left 4 Dead

There are some decent games on the xbox live marketplace. (Metal slug makes for a great co op game.)

[GeneralSnake]

Yeah but I dont really feel like paying 50$ for a source mod. Maybe newegg has some sales on it or something, but l4d does look good.

Has anyone played castle crashers? The xbla game?