Agnés Varda: Mur Murs (1980), a documentary on street art and culture in Los Angeles circa 1980.
I remember seeing this guy's work in a Bicycle Motocross Action magazine ad when I was a kid and thinking it was cool... I'll see if I can dig it up.
Anyway... embedding is disabled but you can watch Mur Murs in six parts on YouTube.
(hat-tip egotripland)
...
UPDATE: Here's that ad from the BMX magazine:
