I think one of my two roommates has a tic. He sniffles constantly. It's getting a little annoying. He seems to show a few signs of autistic traits, but I wouldn't say he has Asperger's syndrome; mostly, he's just extremely introverted.
He's more studious than I am; that's for sure. He doesn't really seem to hang out with friends very much, if ever. He does have a few friends from back home from high school who came up to visit him once, though. He's got a somewhat obsessive-compulsive personality style. He seems very much concerned with order, routine, and being studious. He also plays first-person shooter games a lot. Actually, it's a little bizarre that he laughs while playing them.
To summarize his personality, I would say he's neat (as in tidy), conservative, cleancut, studious, and introverted.