I think my best/worst one to date was whilst mountain biking in Sierra Nevada, Southern Spain. A group of us were riding some very narrow, technical single-track not far from Granada.
As I descended down a steep, off-camber section in a gorge, on feathering the front brake the tyre squirmed to one side on the rim (another puncture! Not aware of) and I did an endo. In my desperation not to fall off the track and 20 foot or so down the gorge side onto rocks, I was flailing my arms about as I went over the bars. My chest was the first thing to hit the hard, compacted trail and then my 30lb, full suspension mountain bike landed on top of me! It smarted a little! Nothing serious though. Just winded and a bruised sternum/ribs for a couple of weeks. As far as MTB crashes go, very tame indeed! I'm hoping my luck holds out!
Matt