This document describes various extreme sports and activities through short definitions: 1) It describes skiing down a steep slope at high speeds and jumping off at the end to see how far one can fly. 2) It also describes climbing down deep ice-covered canyons, diving through an ice-covered sea, climbing mountains, bungee jumping off bridges, whitewater rafting, scuba diving, surfing waves on a board, and skydiving with a parachute opened very late. 3) Many of these activities involve moving quickly down hills and over terrain covered in snow, water or ice using equipment like skis, boats, boards or bikes in a daring manner.