Blue Powerade works wonders. What I do, if I am not too blasted the night before, is get 2 bottles of powerade, put one in the fridge and one next to my bed. When I wake up early to hit the bathroom, pound the powerade next to your bed and go back to sleep for an hour, then get up and sip on the second one while watching saturday morning cartoons. Works like a charm, but if you are still hurting then its time for some hair of the dog, meaning A(singular, one) beer. Also, don't get drunk on shit like coolers or smirnoff ice, that shit will make you diabetic by noon...
Greasy food helps for a hangover, but don't eat greasy food while you are still drunk, your body will stop processing the alcohol and start in on the food, saving the booze until you are done digesting your meal, therefor prolonging your hangover.
Keep in mind that all of these "cures", including this one, are based on personal experience and anecdotal evidence, so you really need to find what works for you; one of my best friends gets 2 day hangovers and has tried pretty much everything, the only thing that works for him is to have a beer the next morning, and he isn't quite in so much pain.