Okay, so when I was little on my bmx (2nd bike) I believe, I used to be able to ride standing and I could ride with no hands. One day I decided to try both at the same time! Nearly impaled myself on the end of the handlebar- lucky I got just a bruise.
Second one is to not reach up to steady a wobbly front fender with your toe. Sometimes one's toe gets caught in the spokes and you get to go for a nice trip over the handlebars. Still have a scar from that one.

