Free Games for my mac?

II_Hazza_II

Ok basically my friend lost his Call of duty 2 cd for his mac but said he didn't want it anymore so said to me i can have the keycode and i can download the game so i did...and i used his keycode and everytime it says it is inuse, and he doesnt play it anymore...

So i would like a good first person shooter that i can play online with my mac if anyone knows any.

Thanks