About 12, neighborhood boys made a ramp with plywood and crates. We were jumping it. Catherine showed up with her giggling friends. I was next. Evel Knevel was popular. I rode to the top of the ramp and stopped ala Knevel to survey the jump. Think teetertotter or seesaw with almost enough weight to balance. Ever so slowly I flopped onto my face with bike, plywood ramp and crate all ending up on top of me some how. I can still hear the giggling gaggle of girls.