I'm a long time windsurfer. It is the ultimate feeling of freedom out on the water on a sunny day with no one around. It is one of the few sports I have done where you forget completely about trading and anything else going on.
Recently I have taken up kitesurfing. It is kind of like windsurfing on steroids. The kites generate insane power, enough to launch you 20 feet high and glide for over 5 seconds is easily possible. It is also quite dangerous (there have been numerous fatalities) which adds to the adrenalin rush.