My worst was a left hook about 10 years ago: I took a minivan to the side, and went down, on my butt, hard. While I was laying in the road, dude comes over and starts yelling at me! In the meantime, there were some homeless people who had a cell phone and called it in. Dude got a pretty serious ticket.

I was in grad school at the time, and had the school insurance that didn't pay for anything. The school clinic basically told me to take Tylenol and that I could go pay for x-rays at a real hospital. I'm pretty sure I broke some ribs, but I remembered that my dad never went in when he broke his ribs, so I didn't either. It wasn't horrible, but I couldn't ride (or sit normally) for a few weeks, and it hurt to cough for a good six months. (Other than needing a wheel true, the bike was ok!)

The other mishap was more recent. I was descending not all that fast, hit a pothole, and somehow ended up in the ditch. Nothing broken other than my pride.

I've learned from both experiences, and it's made me a better rider.