What's the dumbest thing you have ever done that involves injury?

[Pirc Defense]

Had never ridden a motorcycle, but decided to give my friend's Yamaha 250 dirtbike a try. Last thing I remember before, I'm told, driving straight into said friend's house is, "you need to give it more gas."

Knocked me out cold, and my parents let me sleep it off. LOL. My brother always tells me that while I was in my unconscious stupor, I threw a book at him. I don't remember doing this.

My parents subsequently declined to let me have a motorcycle.