sporting events or pursuits characterized by high speeds and high risk. The sports most commonly placed in this group are skateboarding, snowboarding, freestyle skiing, in-line roller-skating, street lugeing, and BMX and mountain biking (cycling). Typically, extreme sports operate outside traditional mainstream sports and are celebrated for their adrenaline-pumping thrills. Racing and acrobatic competitions for motorcycles and snowmobiles are also often classified as “extreme,” and the term can be stretched to include such daring pursuits as rock climbing and skydiving.