6 weeks ago while in Utah, I crashed to avoid plowing through a thicket on my demo board (the Lib Tech Banana - great board, but that's for a different thread) So as I landed on my back, my inertia took me into a group of trees and I hit my back leg on the outside of my knee. Luckily, I was strapped in which prevented my leg from completely wrapping around the tree. I was able to ride down, but I found out when I returned home that I have a cat 2 MCL tear. I was out for 2 weeks but was able to ride on an easy day with a donjoy knee brace. My doctor, specialist and knee brace guy said this was the first MCL injury they every saw due to snowboarding, and I that's why I was able to get back riding early. I now have to wear the brace for every sports activity for at least a year. My riding hasn't been that effected, I can still do pow, trees and bumps, but when I jump, my knee can't handle the landing.
Last year, I landed short on a 20' kicker and jammed my left hand into the snow. When I took my glove off while riding to the bottom, my pinky finger was dislocated and at a 90 degree angle. It hadn't started to swell, and since I had dislocated it before (ski injury when I was 8 and multiple times playing basketball and football) I knew what was in store for me, so w/o thinking, and continuing to ride down, I pulled and reset my finger. I grabbed some snow to keep the swelling down as I rode up the lift to go to ski patrol. By the top, it was OK enough. Again I knew that they would just wrap it up and say be careful. So I stuck my pinky and ring finger in the ring finger part of the glove to give it support and continued to ride - it was a great spring day. I went to the doctors the next day and she said it was set well and won't need a splint or cast but I now should wrap it when I ride and do other stuff. So I duct taped the pinky and ring fingers together on all my winter gloves.

Yet another use for Duct tape.
And I've had a couple concussions too.....