I've never broken a bone either, except for a fracture in my right elbow. When I was younger (around middle school), some friends and I were wrestling on a trampoline. I was lying on my stomach, and one of my fatter friends jumped up and landed on my elbow when I had it extended and facing up, so he basically made it bend backwards. I tried to hide it from my mom but she eventually noticed (and luckily didn't ban me from playing on trampolines as I thought she would.) I just had to wear a sling for a couple of weeks, so it wasn't too bad.