People who do parkour (parkourers?) are an interesting breed.  They jump off really high things, seemingly without hesitation, flip through the air and land like nothing happened.  Most of the time, I get sheer enjoyment out of watching them fly through the air.  When I saw the video below, though, I actually got a little nauseous.  This guy strapped a GoPro to his head, climbed up on to the roof of a four or five story building and jumped to a rooftop a few stories down!