It's hard to believe that there's something with even more caffeine than Mountain Dew, but there is. It's called Game Fuel, specifically marketed in conjunction with the launch of Halo 3, it's vaguely orangey flavored, it's packed with caffeine and sugar, and it's supposed to amp you up.

Does it jolt your senses? Yes.
Does it taste like there's a party in your mouth and everyone's throwing up?
Yes.

Bleh... wont drink this again.