When I was a freshman in high school I went along w/my marching band on a ski trip. Well, I was flying down a slope in front of the lodges when a rock (or something) made my skis twist and made me flip around 3 times in the air while losing my skis and my poles. I landed right on my back shocked as hell. The worst thing about it is that my parents saw the whole thing and thought I had broke my back or neck.
After that, I could move for 2 weeks