Autocross is a proper grassroots motorsport. Competitors hoon around a car park (or other tarmacced area) in order to get the best time possible. It's also noted for being pretty slow, but technically very challenging. Over here it's known as autotesting.
Smooth drivers are rewarded with fast times and victory, while ham-fisted fools are left to flounder near the bottom of the rankings. Some of the UK's most successful rally drivers got their starts in autotesting – the late Colin McRae did, though he used a heavily modified Mini, not a V8-powered Chevy Corvette like the chap in this video.