I remember mine.
I had my left clavicle snapped in a fight the week before, and was still wearing this intensely uncomfortable "figure-8" brace around my shoulders to encourage the bone to set in the right position. (Actually had to wear that for about two months)
I was rather doped up on codeine, though, so I actually allowed my friends to talk me into trying to mosh on the gym floor... nobody else seemed particularly interested in joining, and the only thing they played that was even slightly conducive to moshing was some Oingo Boingo.
Four idiot freshmen jumping around and slamming into each other in the middle of a crowd of disinterested wallflowers.
The next day I had to go back to the doctor's and get my collarbone reset. I took the next three days off from school.