I was bombing it down a hill about 2 years ago on my old Saracen X-ess and hit a stone, the front suspension compressed fully and the wheel buckled inwards, causing one of the spokes to pop out of the rim (I hadn't noticed as I was more pre-occupied with flying over the bars). I landed on top of my bike and tried to stand up (by now the spoke was stuck in the palm of my hand, but I hadn't noticed due to shock) and, as you do, pressed down with my hands to stand up. That's when the spoke forced through behind my right thumb, completely impaling my right hand. Had to be picked up by an ambulance and had the spoke cut off the wheel on the scene, took me to hospital where they knocked my out with an injection in the back of my right hand, woke up a couple of hours later with a bandaged right hand and one hell of a lot of pain.
I can tell you now I'll never feel a stinging pain as bad as that ever again. Possibly comparable to skinning your ballsack and then dipping it in salt and vinegar.