My Favourite Documentary Ever.

Get ready. This was nominated for an Oscar in 1971 and is totally thrilling. It never becomes boring, bringing anyone and everyone into the amazing, exhilarating, funny and sometimes poignant world of motorcycles and the people who ride them. 

"On Any Sunday" (1971)

"A lot more art goes into a film like "On Any Sunday" that might be apparent. It's tremendously hard to get the footage, first of all; a surfer on a wave operates within a relatively small area, but a two-mile motorcycle race requires thousands of feet of footage from several cameras to be adequately covered. Brown has somehow accomplished this (with some financial backing from Steve McQueen, who turns up in the movie a couple of times). What's better, having done it he doesn't tell us about it." 
--Roger Ebert