Snowboarding, Skiing, Wakeboarding, White Water Rafting, Skateboarding, Kite Surfing, Surfing are all classed as Extreme Sports, even Cheese rolling is an extreme sport (if you can call that a sport) and as for the element of risk, you're more likely to die as a pedestrian than you are as a Skydiver!
There's Main Stream Sports and there's Extreme Sports
Richard X