I haven't really dressed up for Halloween since I was a kid. Last year, I just grabbed my judo gi and pretended to be some kind of zombified martial artist. The year before, I wore a headcrab hat one of my roommates got me a few years back… and pretended to a headcrab zombie. You can see the trend.
College was good for debauchery, "experimenting," and surprisingly, video games. I guess I learned some things too, but, eh. Academics was the least interesting part of college for me.