parkour is damn fun, been doing it on and off for about a year, my friend is into it in a big way, but me him and a few other guys have been going to a gym for the last few years that have soft blocks, tumble tracks, padded floor etc so when we discovered parkour we already had the place to practice it (relativly) safely.
i dont really do it much outside of the gym besides doing a few flips here and there (i know its not parkour but its fun) but he does it outside and goes to the various jams and such
this is the scene in my area
http://www.southcoastparkour.co.uk/
as for the sport of kings.....
i found THE best spectator sport while on a nsowboarding trip in france last week.
im agine a trench full of water about 3 metres wide and about 10 metres long, in a snowy landscape with a hill running up to it.
then a bunch of skiiers hurtling down the hill (sometimes without shirts) and attemtping to skim across the trench and make it to the otherside
i have some videos on my phone, ill see if i can get them on the computer
anyways now that its the summer im gonna start again