I want to tell you about a mod for C&C Generals Zero Hour called "Contra" (i know the game is old *very old*) but this mod makes it a lot better and i play it with my friends on hamachi and it is a lot of fun :D
http://www.youtube.com/watch?v=gU7mVGUNhKo&feature=related
Here is a link for the mod's website
http://contra.cncguild.net/
Have fun and let me know if anyone's up for a challenge ;)