I've gotten mildly tipsy once in my life. It was an intere4sting and not-unenjoyable feeling, but it just wasn't my style.
For one thing, your physical reaction speed will slow down. This means that if you try waving your arm, your 'real' arm will be lagging behind your 'imagined' arm. It feels sort of like your spirit is moving at the same speed it always does, and your body is trying to play catch-up.
It's not normally that huge a delay, but it can kinda freak you out a bit. I spent a very long time staring at my hands as I waved them around, and marveling at how they didn't seem to be as responsive as they used to. An interesting side/sister effect of this is that all your movements will seem to take on a very fluid quality, and you'll just seem to "flow".
Then again, I may just be easily entertained when I'm drunk.
Second, the way you interact with people and your environment will change. First of all, the more alcohol you imbibe, the more you love the people around you. A few drinks and you're ready to give that creepy stalker-dude a second chance, quite a few drinks and you're surrounded by your dear friends wherever you go, and several liquor bottles later you discover that everyone in the world is your soulmate.
Also, your inhibitions drop. I found myself thinking aloud quite a bit, and giggling/talking far more than I usually do. You'll feel more comfortable doing more things. This is a very interesting effect from a research standpoint, since as your confidence goes up your aptitude goes down. Very fun stuff.
Of course, you'll be schnockered, so you won't care all that much. I LOVE YOU!
You'll also develop your own personal quirks for when you are drunk. I know someone who tackles people when he gets drunk, and I personally set about finding straight lines to walk along to test how drunk I am. Your personal flavor is almost impossible to predict. You just have to find out.
Personally, I enjoyed my time under the influence, and I'm glad I experienced it. But I don't see myself doing it all that much in the future. I will probably do it for the reunion party that's coming up, but that's mainly because I open up more and talk to people when I'm drunk, and I'd like to get as much out of these people as I can, seeing as I don't talk with them that often.
If you're thinking about trying it, I recommend you find an experienced drinker to guide you through the process. Not an alcoholic, and not just someone who is looking for a drinking buddy. That will just make things worse. Find someone who has a fair amount of experience drinking and will be able to help you determine when you've had enough.
PROTIP: Drink tons of water. Seriously. Guzzle the stuff. All night long. You can never have too much, and what you think is enough probably won't cover it. You won't kill your buzz, but you will kill (or at least severely maim) the morning after. And it's loads of fun to be bouncing around and alert while all your buddies are holding their heads and chanting the mantra of "never again... never again... never..."