http://www.youtube.com/watch?feature=player_embedded&v=xNouiE7f4uA

The Colorado Department of Safety (CDOT) released this video showing what the potential is for injury when you aren't wearing any gear. CO doesn't have a helmet law in place, which would certainly help. 

I just wish the end comment by the guy in the video included the rest of his body. 

(video seems graphic, but it's fake)