I have seen insanity and it happens on the streets of Valparaiso, Chile. The Valparaiso Cerro Abajo Race is a legendary urban bike race and is more extreme than skydiving out of an exploding F-18 piloted by Charlie Sheen – while chugging a 2 liter of Mountain Dew. The rider must brave jumps, stray dogs, and flights of stairs along the steep downhill path. The first person perspective provided by the excellent helmet cam lets us take in every glorious and frightening detail. Do yourself a favor and watch this one in full screen mode.
Also, check out this roundup from the 2011 race, which was won by Filip Polc.