Riding rapidly down our street on my tree-speed bike at about age 11, I decided to roll the wheels 1/2 way up the curved curb...an early attempt at trick riding. I found I could hold it and ride steadily with the wheels about 1/2 way up the curb radius I musta been doing about 30 when I got to the curve in the road where part of the curb that was missing a 1/2 foot section. I didn't see it till the last nano-moment.
The next thing I knew I was laying on the grass of the neighbors's lawn, glasses akimbo, me beaten to hell, and the handlebars twisted so far around that they lined up with the wheels and frame.
No permanent damage, but it put me off bicycle rodeoing for a time.