There's an energy drink the entertainers use at work, I forget the name, but it's all natural and has no caffeine.. I'm trying so hard to remember the name. I know it has an "X" on the can though and the cans are shaped similarly to red bull's.
Personally I like using Emergen-C as my energy booster of choice. 100mg of Vitamin C... and it really does work. And it comes in a couple different flavors :)