My senior year I managed to find space for 5 bikes in my on-campus apartment. It was originally built as a 1 bedroom, so when the school bought the properties and converted them to two "bedroom" apartments, the common/living area became a bedroom. My friend/roommate got the bedroom and I got what amounted to the living room. His room had two small closets, so I kept my downhill bike in one of them, since he got the better room. My touring bike hung above my desk on ladder hangers. My xc bike slept under my bed (which was lifted on "rack raisers"). My fixed gear hung by the pipes in the hall and my bmx was wedged into the corner behind the door. It was tight, but it worked well.

You'll learn a lot in college, including effective use of small spaces. Hang out at Home Depot and learn about all the different fun ways to hang/store crap.