Windows PC games with Local Co-op mode

Not many PC games get released with local co op which makes PCs a less social console. Especially Racing games which are well suited to it.
This thread is for people to post recent PC titles with local co op (running on one pc) modes.
I'll start us off:

Trine
Audiosurf (to some extent)
Guitar Hero 3
Street Fighter 4

 

Serious Sam 1 and 2.

That is all.

 

I'm gonna assume local multiplayer counts in this lot, but if you really want co-op, just play both humans against the computer.

The Worms/Civ games have hot-seating - not ideal, but not too bad.
I'm sure the big sports games (Fifa, Pes, etc) have local multiplayer.
Ummm... you could huddle 2 people around Theme Park/World/Rollercoaster Tycoon? xD

 

This is something that I really wish more games had. I set up Serious Sam with gamepads for the single player campaign and it was quite fun!

For anyone who hasn't seen it yet, try http://www.co-optimus.com/ - an excellent place to discover if a game has local co-op.

 

There is always l4d. I've played a many a games with my girlfriend, her on the xbox controller. and me on the keyboard/mouse.

 

Cool, I didn't know l4d had local co op. Hopefully this will be in l4d2 aswell, which I've got on pre-order .