Before you go to bed drink as much water as you can. Of course the problem is that when you are really smashed is when you forget about the water and then the next day you wake up and remember that you forgot to drink the water. However drinking the water the night before will prevent the hangover so you don't have to look for a cure for it.
Of course since I am on day 5 right now I don't have to worry about it anymore.
Scott