Ken Block's incredible Gymkhana series of stunt-driving videos, sponsored by DC Shoes, are among the most successful examples of branded content ever—just look at the YouTube view counts, which run into the tens of millions. (Two of the clips also rank among the four most-shared ads ever, according to Unruly Media.) Now, Block is out with Gymkhana Five, in which he scorches San Francisco with his typical crazy, squeally moves. Filmed over four days by director Ben Conrad, it features cameos by Travis Pastrana on his dirtbike and Jake Phelps of Thrasher magazine fame. Fasten your seatbelt and watch below. Via Unruly.