While I haven't found any real cure for hangovers, there are things that make them more tolerable.
First of all, try to sleep it off as much as you can.
For breakfast, east something greasy and filling. Something like fried eggs and bacon, with two pieces of toast. Drink some coffee to get rid of the sleepiness, but keep in mind that it dehydrates you.
Throughout the day, keep drinking water. Hydration reduces the uncomfortable feeling. Also, multivitamins help restore the balance of vitamins and minerals in the body. The main cause of a hangover is a disruption of that balance.
Take some pain relievers if the headaches get too bad.
Eat as much as you can comfortably handle during lunch and dinner. Chicken soup works wonders for combatting the nasty feeling in the stomach during hangovers.
Go to bed early to catch up on the sleep.