Was riding down a quiet residential street eons ago... and watching myself pedal... watching the movement of my legs and how they interacted with the pedals and cranks... Quite amusing actually.
Well I would look around, make sure nothing was in my path, and then glance back at my rapidly spinning legs, then look up again. Only one time I did not look up soon enough... and I must have drifted a bit.
I ran smack into the back of a camper shell that was parked on the side of the road, but up on stands. There was nothing underneath it... it was just a shell at truck height as if the owner had lifted the shell and pulled the truck out and had driven off.
I wasn't going terribly fast, but the impact was enough to flatten me right up against the back of the shell in a cartoon like way... SMACK!
The bike was fine, it just rolled under the shell... but my face and chest took the full brunt of the impact. Man, I felt stupid!
I shook it off and rode on... avoided that street forever.