I've actually never broke a bone... but what was really painful was my grades XD. No just kidding. I was walking and I fell, making the carpet rub against my elbow, and it got my skin just coming off ;-;
But seriously, one of them being accidentally having my hand hit on a broken glass. It was painful.
I accidentally fell down when running, having both of my knees hurt so much that they were both bleeding (thank God nothing happened to the bones, though).
I slept, then woke up, and realized that the pillow was covered by my nose blood. My nose use to be so easy to break and bleed.
I can't decide... Either the time I tripped over a ball and fell and slid across onto the pavement, or when a dentist accidentally drilled my tongue...
Or the time I fell and someone tripped over me and sat on my face. At least he didn't fart...