agreed, definitely wear a helmet, I never ski without one because I've had 6 concussions but even if you haven't had any you're crazy if you don't wear one. Another good idea is a mouthguard, a lot of concussions are caused by your jaws slamming together really hard, I've had concussions while wearing a helmet where I overshot and cranked my chin on my knees that I probably wouldn't have gotten if I was wearing a mouthguard.
'Ok, punching ain't your thing...but that's ok, you're not that kind of fighter!' -Moe