i live in SD and know about 20 people that go to UCSD right now.
if you're the kind of person who wants to party every night and get drunk any time you can, then go to santa barbara.
SDSU parties are where UCSD students go to do that kind of thing. It's close though.
There's also downtown San Diego and the Gaslamp Quarter which is actually quite cool.
You can also go to Pacific Beach if you have a car or a Coaster ticket. There's a lot of nightlife there.
And when all else fails.....TIJUANA