Super Mario Crossover
This here's another great one for lots of cool characters, except this time, they're NES characters! Retro geeky greatness! My personal favorite is the Contra guy that I am too lazy to check the actual name of. Shooting down goombas with a machine gun never gets old. Actually, I'll have to admit that my real favorite character isn't even on this version. It's the awesome tank thing I also forgot the name of on the updated version. You can play that version at ExplodingRabbit.com. I hope an updated publicly available version gets released soon...though it probably won't. This makes me sad.