bonsai trees require a LOT of maintenance. I had one for a while and it died... 
First off, they're damn expensive (unless you grow your own, but that takes a LOOONNNG time). Second, they require more light than you could probably provide in the average dorm room. Third, they require constant care that college students usually aren't responsible enough to provide 

.
Maybe you'd have more luck than I, but I thought I took pretty good care of it (it was a juniper) but I guess not...
hehe just don't feed it beer.
l2c