Dem bones are useless
Popular Science voted for this Flash site as the "useless site of the month", but you'll have fun playing with it anyway. You can make a skeleton walk, dance, fly and perform all kinds of unnatural movements. Lots of options (just about everything is clickable/movable).
Looking for something on Flash usability? Try this report from User Interface Engineering. I saw some of their material recently, and it was rather interesting.