You want painful? Hows this... I was rollerskating with a friend at this construction site for a large office building. There was a nice large flat newly poured concrete floor, so we decided to go skate around. Well, I was going to fast around a corner and wiped out. On the ground, there was a piece of wood sticking out of the ground (some sort of marker I'd guess) about 1 1/2 inches long by 1/8 inch wide by 12 inches tall. Well, I managed to come down with my right forearm right on top of this fairly sharp wooden stake, and drove it right through my arm (in through the bottom, out the top of my forearm) :Q. My friend literally pulled me off the stake, after which my dad took me to the ER where they had to do some serious grafting and fixing. No long term damage though, just a 2 inch scar on either side