Take two people one sphere and a sizeable hill and what have you got this is a fun extreme activity which will see you writhing around in a spherical universe where the sky is the ground and the ground is the sky and your stomach made a bid for freedom some time ago youll love it with no harnesses you are completely free in the sphere as you and a friend slip and slide around inside the ball with thirty litres of water instead of being thrown around with the ball link arms with your fri