Most of my injuries have been pride-related, which is interesting given that I've done so many things which really should have injured me.
I did have some bruising of the posterior when I was first learning to play Greenhorn in stiletto heels.
I've gone flying off a DDR machine several times (this usually happens when I've just gotten new shoes and don't know all the places they're going to catch on yet), but been miraculously uninjured.
I nearly broke my own kneecaps once coming to an unexpected stop during R3 Heavy Doubles - I'm not quite sure what exactly I did to them, but they made this unpleasant cracking noise and were essentially immobile for several days. A little kid had wandered onto the right side of the machine while I was on the left, and I nearly smooshed him when I went to cross over!
As it was, I failed the song. Then I chastised him ungraciously. Then his father and I argued for a while about whose responsibility it was to keep his kid from getting injured in the arcade. (Hint: I didn't think it was mine.)
If his father had started a fistfight with me, would that have counted as a DDR injury?
Either way, I'd have nothing on the girl who had the heart attack.