Parkour (sometimes abbreviated to PK) or l'art du déplacement. (English: the art of displacement) is an activity with the aim of moving from one point to another as efficiently and quickly as possible, using principally the abilities of the human body. It is meant to help one overcome obstacles, which can be anything in the surrounding environment — from branches and rocks to rails and concrete walls — and can be practiced in both rural and urban areas. Male parkour practitioners are recognized as traceurs and female as traceuses.

Founded by David Belle in France, parkour focuses on practicing efficient movements to develop your body and mind to be able to overcome obstacles in an emergency. Also may be a form of entertainment or as a pastime.

The above def. I stole from the voluminous Wikipedia entry on the subject.

Since pics are worth 1000 words, videos should be worth... hmmm, carry the 6, times 30fps... forget it, here are three impressive parkour clips...

This is the first vid I'd ever seen of parkour. A bit long, but impressive.(8.24)...



Here's a good compilation showing a lot of the individual moves(3.37)...



Finally, this guy is almost comically athletic...