For your adrenalin rush of the day, here’s a wicked downhill run on BMX bikes (one of which is brakeless), which takes place on Hunt Hill in San Francisco’s Marin Headlands:
And if you want to bomb down this same hill, here are the directions, courtesy of a comment on the Vimeo page:
Video by Werehaus, shot with a hood-mounted Canon 5D.
[h/t to SHFT]