Caving - If you're caving you'll have a helmet and a head torch so why not add a Go Pro camera such as the helmet hero. This way you can get some excellent atmospheric footage of your exploration and some recordings of whatever you find. The great thing about a Go Pro camera is that they're mostly waterproof to about 60 meters meaning you don't need to worry if you get wet or fall over.
Spelunking - Spelunking is a kind of cross between abseiling and caving where you lower yourself into the cave via a rope. This then leaves you hanging in the great open expanse which can have a great feeling of adventure and characterize some remarkable views.
Football - A Go Pro camera doesn't only need to be used for ultimate sports and sports spirited big engines. And with the Go Pro Naked for example you can fasten a camera to yourself without the need for a helmet (which you make you look a bit ridiculous on the pitch). If you really enjoy your sport then, be it football, rugby, hockey, basketball, cricket or whatever else - then why not get some great footage that will make you look like a pro when you play it back and that can also help you to critique your own technique.
Parkour - Parkour is fast becoming a phenomenon. Also known as free running, it essentially involves running over roof-tops, flipping off of tables and scaling high walls in a fashion similar to Spider-Man or Jackie Chan. This of course is one of the most visually remarkable activities out there and can advantage greatly from some great camera work. Using a Go Pro camera you can get a first person angle on the activity which will be great when edited into your online 'sampler' (the video demonstration of a traceur's skills that they tend to upload to YouTube). This is also a great occasion to get some really iconic photographs of you or a friend navigation through the air.
Martial Arts - Watching a fight back from your own eye view can be a great and spirited experience, and again martial arts provide many opportunities for those 'cool' moments where you deliver a great roundhouse to the head or block and counter an attack.
Jet Skiing - Jet Skiing is a very fast sport that requires a high def camera to capture all the individual drops of water as well as a high frame rate to capture the scenery as it speeds by. Both scenic and fast, this can make for some spirited videos and some great still shots.
Snowboarding/Skiing - Snowboarding and skiing are two activities that highlight great locations (snow covered mountain peeks to be specific) as well as high speeds and lots of spirited jumps. All of these will translate excellently to video and make for some excellent photographs.
Rock Climbing - Rock climbing is an additional one incredibly visually impressive activity that not only involves many technical and hazardous moves but also some remarkable vistas and views. Again this makes for some great photo-ops too and would look great on anyone's wall.
Sports and Events That Can advantage From a Go Pro Camera