Introducing: Kendo: the art of Japanese Fencing. I can't think of another place you'll get to scream until your lungs are empty and whack people in the head with a stick.
Of course, it's rather more complicated than that, but you get the idea.
Kendo is a very good stress reliever. VERY good. After a workout you'll be quivering like jelly with all your stresses replaced, at least for a while, with a comforting sense of calm. During a workout you don't have time to think about your troubles because you'll be focusing on your posture, breathing, footwork, technique and the person who's about to be swinging a stick at your head. There's nothing like the latter to make you focus on the NOW.
For more information, visit the Hayakawa Kendo Club at http://www.kendoniagara.com.
Below is an example of sparring in Kendo. Watch for the points!