Heh. Mine's nothing compared to yours...
My most painful, I must say, is when I fractured the cartilage in my nose.
I was playing football, no pads or anything. Me and this other kid jumped for the football; the kid's knee first sunk into my crotch, making me bend over just in time for his other knee to smack sideways into my nose.
Long story short: Fell on the ground, kids started crowding, I got pissed, got up...Then my nose started bleeding. Loootttssss of bloods.
Not to mention the burning pain in my testicles. >.<