This video was issued by MotoGP themselves. It's a brutal reel of crashes from the 2012 season. Highsides, lowsides, wipeouts - it's got the lot. The text under the video says it all:
"Coming off a motorcycle is never a nice experience, yet sometimes one needs to be reminded just what the MotoGP™ riders risk when they head out on track, to truly appreciate the skill required with such powerful machines."