The worst was probably splintering my tailbone. Apparently I have oddly dense bones, so they don't like to full out break, but just splinter.

I was snowboarding and trying to keep up with my mom. At the very very end of the run, I snagged my back edge and got slapped so hard to the ground, I'm pretty sure I blacked out for a few seconds (wear a helmet, kids). We rode the rest of the day and I don't remember much about it all except my butt hurt so bad. I couldn't sit down normally for over a year. I sat on my knees or in a snow tube in the living room because I couldn't stand to sit on the couch or in a chair at all.

A separate incident that might also tie for worst, but I think I fractured my skull when I was around 8? It could just be one of the growth plates, but I have a scar in my skin, and then a serious dent in my forehead in the skull which is attached to a long crack that goes down to my eyebrow before I'm not able to feel it anymore. We didn't go to the hospital or anything, I just dealt with the swelling and the small split. I did dent the corner beam in our house though. Thick skull I guess?