I teach private music lessons (piano, recorder and harpsichord) and writing. I have a teen writing group that was supposed to be a 5 day class a year ago and several of the kids refused to quit. They asked me to continue it and we still meet every two weeks for writing exercises and critiques.
I used to teach adult classes on one of my favorite subjects: women in medieval history.
Though I love to teach, I have to say, I'm with Dianne also--I love attending classes. I spent a lot of time returning to college and was actually sad when I finally graduated at the age of 37. I keep thinking I could go back for my masters but now I'm having too much fun as a writer, plus we're trying to get 2 kids through college at the moment.