Hit a nice short one, a base with the pole removed, endo'd and nearly cut the end of my thumb off. I can only assume it ended up in my front wheel/spokes while I was going over.
Fortunately, a fellow (my Guardian Angel that day - God watches over us fools) was at his diesel shop just off the trail on his day off and drove me the 50 or so miles to the nearest hospital, and my thumb lives on.
The bike suffered bent top and down tubes and the frame is now a stool. Steel is recyclable.