I have a few, but most can wait until I've had some sleep as I've just got home from Thirsk.
One that sticks in my mind though, was a rider at 5am yesterday while I marshalling. He misjudged the entrance to the control, got caught up on the curved curb, and rode straight into the brick gatepost!
Luckily he wasn't hurt, but his front wheel got stuck in between the back of the school gate, and the post, so the rim was pringled. I'm hoping he made it back as I got the wheel just about straight, but the tensions were that far off even in places you could have played it like a harp.