Le Parkour

Le Parkour is a cross between an extreme sport, a suicidal mental disorder and a form of urban ballet. This activity, which was invented by one David Belle in the French suburbs (yes, they do more there than rioting and burning cars), involves jumping onto, down from, through and over various obstacles, scaling walls that seem unscalable to mere mortals, leaping from rooftops onto concrete floor several meters below, and generally laughing in the face of danger and slipping ice cubes down the vest of fear.
The Le Parkour Web site has a number of videos of Belle and his friends and competitors doing stuff that makes extreme skateboarders look like a bunch of sissies. Apparently, Luc Besson (he of "Léon" and "Taxi" fame) made a movie about them; I guess it didn't make it to my local cinema. In short: awesome stuff.