WHAT??? DO YOU HAVE A HANGOVER??? SPEAK UP, I CAN'T HEAR YOU!!!
(At least, that's what my fraternity brothers would have done to "cure" a hangover.

)
Seriously - best cure is to hydrate yourself beyond any form of hydration. Hangovers are generally a result of a loss of water... drink drink drink drink (water, not the other stuff).
Moe.