Last game i went to and I had some coconut water and that really did the trick. But only during break. Coconut water might be the best thing for your body that isn't made artificially. If I am not mistaken, you can actually use coconut water as an IV drip.
But I usually cram my hydration pack full of ice cubes and then fill up with water. A bit of cold water in the middle of a firefight is a nice little boost of energy.
Imagine Whirled Peas