I had Stephen for my Introduction to 21st Century Archaeology class last semester and he was awesome. He's been doing field work in the Andes with Professor D'Altroy, so I don't know if or when he'll be a TA again. If you ever do get the chance to have him for discussion sections, though, I can't recommend him highly enough. My section met at 10am on friday mornings, so the few kids that showed up were usually hungover, as was he, but somehow we still managed to get into some great discussions. He's not a hard grader, and was really helpful in clearing up some of the more abstract/theoretical concepts that I found hard to grasp. Really though, he's rad.