Could definitly be the time somewhere around 12 years old, early stages of bike mechanic tinkering. I had adjusted the handlebar stem on my stingray and took it out for a test run (my parent's house stood at the top of a large hill). I started pedaling down the hill when I realized the virtue of tightening stem bolts. The bars pulled loose in my hand and I did my best Superman impersonation when the front wheel flipped perpendicular to the frame (and direction of travel). Ended up with stitches in my left knee and an assortment of bumps and scrapes.

Unless you count the horizontal track stand I did last summer on a commute home, right after I went with clippless pedals. Definitly left some bark on that one too.