I've seen a video of a guy snowboarding down a mountain with a Canon 5D Mk2 and it was freaking absolutely AMAZING!!!!!!!!
Looked like it was down for a hollywood movie!!!
I was quite impressed and will see if I can fine the UTube link for it.
Here it is it is a MUST WATCH video shot with a Canon 5D MkII
YouTube - Provo P.O.V