about 5
2 were football related
one I was camping and inebriated and tripped on the root of a tree and fell head first into it
one happened on campus after an ice storm, I slipped on ice and the back of my head softened the landing for the rest of me.
The first one I ever got was the most badass of them all though! I tried to ramp my Huffy off a crudely built ramp constructed by my brother.... the ramp broke, my front wheel got stuck and I was propelled off of the bike head first into a fire hydrant. I was 8, and I felt pretty badass getting stitches.