When no one is around, I tend not to wear clothes. In general, I don't keep my shirt on unless I have to and if no one's around, I may as well not wear any pants either. In addition, I tend to play around with snatches of dialogue or phrases I find interesting. More than once a friend or roommate has walked in on me, pacing around, naked and muttering seemingly inane phrases to myself.
When it's just you in the house, what do you do?