When I was in Korea, I had a horrible hangover one Saturday. I had to teach about two hours to various students. Fortunately, the first two groups were very kind children. The last group were brats.
So, I dragged myself into the pharmacy and explained my situation. The man gave me two pills and a small bottle to drink it with. The stuff was sweet and nasty, but in a half hour my headache and pain were gone!
But, alas, I don’t know what it was. Ask a Korean.
Annyong Hayseyo!
Aside from the re-hydrate yourself, I use two things: Milk Thistle and pot. Milk Thistle is supposed to help your liver, so I take a pill before drinking, before sleeping and then upon waking. I think it helps your liver do its job. It seems to take that ‘icky’ feeling away in the morning, YMMV.
You know all the reasons for legalizing medicinal marijuana: relieves headaches, bodyaches, nausea, etc. in cancer patients. Sound familiar? You can take just a small amount- 1/4 to 1/2 a hit, just enough to take the edge off and not make you stoned. Within 5 minutes you will feel noticably better, including being able to actually get something done that day, if needed. Conversely, if your day is shot to hell anyways now that you are hung-over, it’s not as if you are going to be any more productive remaining sober and in pain…So you could smoke a joint that would make Bob Marley jealous and not feel anything at all! 
But seriously, having just a bit of pot has made the difference between lying on the couch suffering and being able to get up and do something.
And I second the warnings on Tylenol- When people attempt suicide by Tylenol, they don’t take so many pills that their heart or breathing stops…normally what it does is destroys the liver and they die after a few days from toxins in their system that can’t be gotten rid of. So now you have just done damage to your liver from alcohol and then you add something that also damages your liver…bad combo. Switch to Aspirin and do yourself a favor.
-Tcat
Let’s resist the temptation to advocate the use of illegal drugs, okay folks?
Since the OP is looking for advice more than facts, I’ll move this thread to IMHO.
bibliophage
moderator GQ
I apologize, bibliophage. I should have kept that to “I do” point of view, not “You can…”
-Tcat
I often drink rehydration salts, which are for electrolyte replacement in the case of diaorreah. They’re very inexpensive and available from all good pharmacists.
I don’t know why it works, but try eating lots of starchy food. Rice is good. Rice wrapped in a tortilla (with whatever else you like on your burritos, but skip the hot sauce) is better.
I recently discovered that a big glass or two of milk at the end of the evening did absolute wonders at preventing a hangover from indulging in the grapes of wrath. I don’t know if it works for spirits other than wine because it’s about the only thing I ever drink. But at least for it, I’ve felt absolutely no ill effects the last several times when I probably should have been a hurting pup the next day.
One caveat, the mixing of wine and milk is likely to give you absolutely prodigious volumes of lethal buttgas early the next mourn.
There’s a product called “Emergen-C” that you can get at health food stores. It’s a powder that you mix with water and has a zillion different vitamins (chiefly C, of course) in it. It tastes like a bit like lemon-flavored Alka-Seltzer; not too bad.
Anyway, drinking one of those before bed works wonders. If you wake up with a bad hangover, I recommend water, coffee, vitamin C, and spicy food (works for me). Also some moderate exercise, like taking a walk or something, will help.
Anecdote: We were shooting a movie last summer and I’d been at a party until very, very late the night before, so I showed up to the shoot after about three hours’ sleep and feeling like what the cat drug in. The director decided our first shot of the day would be to dance our butts off and look like we were having the time of our lives for about a minute and a half. I felt absolutely terrible and the scene was torture (thank heaven we only had to do one take), but after just one short song’s worth of dancing I felt much, much better. I was wide awake, my heart started pumping, my head cleared, etc. I was still a little tired, but far better than I had been before.
I’ve always used the Gatorade and banana remedy*, to replenish electrolytes and potassium. But upon reading about the amount of sugar in Gatorade, I must second the Pedialyte as a good subsitute. It costs about twice as much, but it isn’t sugar-laden, and therefore would help prevent further dehydration.
*back in my college days, when I overindulged more frequently
Pretzels and grapefruit juice always work well for me!
Eating before bed also a good one!
And lastly, chicken noodle soup for breakfast… 
I’ve always found a real (i.e. not diet) Coke, plus two each of Tylenol and Sudafed helps a lot. I don’t know why the sugared Coke seems to work so much better than diet.
Of course combination acetominophen-pseudoephedrine pills work just as well.
The Hamburglar has stolen all the vowels from this post!
This site seems to have the very answer to your question. Seems to be a composite of all of the answers listed above.
http://www.soyouwanna.com/site/syws/hangover/hangover.html
I strongly, strongly recommend the juice next-day treatment. Works really well with a wine hangover…and I should know.
I like lots of V8 and a greasy grilled cheese sandwich, although gatorade works well too.
A friend of mine had a hangover ritual down to a science (he is now on the wagon.) He would perform a “hangover exorcism” which uses even more heinous things against the hangover. In this ritual he would eat hot italian sausage with peppers and onions with a six pack of boylans grape soda while blasting Black Sabbath. No wonder he had to quit drinking.
I’m going to add another stanza to my song of Tim Horton’s praise.
The best hangover cure I’ve come across so far is a glass of water (of course), a couple Advils and a Tim Horton’s iced capuccino. It has:
-caffiene
-lots of fat
-water - negated by the caffiene content, no doubt, but good for your dry mouth
And while you’re there, you might as well get a bagel w/ cream cheese to add some more fat and some starch.
Well, this is more a preventative strategy than a cure: I’ve found restricting the initial imbibing to vodka and water (with a twist, if you like) to be fairly effective. Boring maybe but, I’m not usually drinking for the sake of my taste buds anyhow. 
It seems to help keep you semi-hydrated throughout the evening. The continuous trips to pee probably don’t hurt either.
As a bonus, the alchohol dilution seems to help keep the Likkered-Up Asshole Syndrome from rearing it’s ugly head, while producing a nice, clean buzz. (No guarantees, of course.)
Other than that, I’ve also found that lots of water & and just one or two tylenol before bed helps.
Morning after, getting up and moving around, coffee and eating something ASAP helps dissipate the last of the yucks.