Depends on how much time I think I can stand being around people. If its a lot, the "usual" thing in the college town I'm at for school. Drink heavily with no purpose, with what seems like the same ten or so people. Not healthy, not productive, but I will actually sleep in for a change the next day. If I'm not in a drinking mood (usually means I'm not in a good mood, or I don't feel like dealing with people, or I'm just worn out) then I just kinda watch television and mess with my computer, maybe play with my cat some. If I'm in the up cycle for WoW, I may play. If I'm in the down cycle, the aforementioned television / interweb stuff.
Most weekends, and days I don't have anything to do for that matter, I just turn on the television and surf the net for hours, trying to keep from being miserably bored. Definitely planning on getting a job this semester. Something to do and some disposable income to boot.