I first read about Parkour in an issue of Warren Ellis' Global Frequency. Take a look at the cover.
Parkour (IPA: /paʁ.'kuʁ/, often abbreviated PK) is a physical discipline of French origin in which participants attempt to pass obstacles in the fastest and most direct manner possible, using skills such as jumping, vaulting and climbing, or the more specific parkour moves. The obstacles can be anything in one's environment, so parkour is often practiced in urban areas because of many suitable public structures, such as buildings, rails, and walls.
A traceur (/tʁa.'sœʁ/) is a participant of parkour.
I'm not going to stop mocking the french for only winning wars when lead by foreigners and teenage girls, but this is pretty cool.