Prepare to be astounded and bedazzled, I am..Three d.....sorry, too much Fallout 3.
Anyway, when I was seven I think, my younger sister and I were playing follow the leader, I was walking ahead of her with a flute in my mouth, she cheated(!) and ran ahead of me, I inturn ran ahead of her, turned back to gloat, then turned my head to face where I was going, which as it turned out, was straight into a wall.
As I said I had a flute in my mouth(well a tin whistle actually, but I'm not sure if you all know what those accursed little things are so I just said flute).
Anyway, the flute(whistle) hit into the wall and rammed into my throat, gouging a large hole, I started coughing up blood and well, it wasn't nice.
We went to the hospital but there wasn't actually anything they could do, the only thing to do was wait for the wound to heal.
I was incredibly lucky, as had the flute(whistle) hit an inch further to the left, it would have been a lot worse, possibly even fatal.
So yeah, that's probably the stupidest thing I ever did as a child, but on the up-side it did teach me to watch where I'm bloody well going.