I was going down some stairs when I was about 15, 6 steps from the bottom I decided to just jump the rest of them and save 1.37 seconds of my life. I jumped to far forward and hit my head on an overhang from the ceiling, and dented it in. Physics kicked in an my head stopped moving but my feet swung out under me and I landed on the back of my head on a tile floor. Totally scared the shit outta everyone around me but I got up and walked away like it was no big deal, how I didn't crack my head like a coconut I have no idea.