I've had a few professors like that too. I usually just laugh my ass off during class if they do something funny. One of my archaeology teachers was a Paleoscatologist. Yes, it's what you think it is. About half-way through the year, someone asked why he became a Paleoscatologist...he blurted out, "Well, let's just say that I really know my shit." I laughed hysterically for a couple of minutes. Like three other people laughed. The teacher really got a kick out of it and I ended up making a good grade.
I always laugh at the teachers and especially their jokes...they like the students that appreciate weird senses of humor.
-Lasereth