Bouldering

Found this short film on YouTube that shows some great bouldering. 

Bouldering is definitely my favourite part of rock climbing. Ascending 37 feet off the ground is thrilling, but there's no way you'll challenge yourself – especially mentally – as much you will on a bouldering route. Take away the height and the need for ropes and a belayer and it's just you and your problem to work out. It forces you (at least, once you get past the easiest routes) to use proper technique, and it makes you use your whole body from the tips of your fingers to the tips of your toes to get to the final hold.

It's got to be one of the best workouts, both for your body and your brain.