I know I'm not alone in saying that I've been hurt on a teeter-totter (or see-saw if you prefer). I've heard many stories from friends, but no one quite like mine. More than once I was up in the air when the other rider decided to get off.
This was much worse than that.
I don't remember how old I was --maybe 7. I decided to sit in the middle of the teeter-totter while my friends rode up and down. I sat on some plastic thing that covered the bar and gripped it with my fingers. As the see sawed, the metal of the the teeter-totter crushed my pinky against the metal of the support bar. It is said that my dad could hear me scream 4 baseball fields away.
A chipped bone and a bunch of stitches later, I was doing ok. But I will always have an inch-long valley through my right pinky fingertip.
I am actually very grateful that that was the worst injury of my 30-odd years.