Gratuitous amount of calorie flux does it for me. Eat hearty high calorie foods (bagel, heavy cream and cheese, animal fat, etc), burning calories also helps a lot.. breathe in some fresh air, get your heart pumping and your liver working. Works wonders.
For those looking for a health conscious cure for hangovers.... uh... don't fill yourself with poison in the first place. Because lets not forget, alcohol is poison.
I also have a hangover prevention routine that has worked 100% of the time for me when I've made a point to follow each step. 10 minutes before you go to bed, stop drinking, have a multi-vitamin, an entire bottle of water, and brush your teeth.. boom, no hangover.