I love doing quick sketches of people in the street. For a while there I was doing a good hour of these every day. That's fallen off a bit lately, what with comics and all, but I still carry a mini-sketckbook wherever I go and get in a few sketches when I can...
... and paintings. Something else that's fallen off a bit lately - I used to draw and teach once a week. Still, you didn't come here for pictures of naked people anyway, did you?
Basically everything that doesn't fit anywhere else. Some doodles, character studies, comics exploratory ideas, drawing on location, studies from photographs etc etc...