Physics was awesome for me. And having a great teacher didn't hurt, either. He had us do some of the craziest things for labs, and he made up most of the assignments off of the top of his head (which made for some very interesting results... like a football punter kicking a ball 1.5km... ah vectors...)
I think my favorite part about the class was the last four or five weeks of school, our assignment was to build a trebuchet that would launch a golf ball as far as possible. The other team made one out of K'NEX. While it was a cool design, it only launched the golf ball around five or six meters. Our team, on the other hand, built a nine foot tall monstrosity. We couldn't find the golf ball after our first shot. (We had originally designed it to throw watermelons or pumpkins, hehe.)