In short… a TON of people roll down a hill after a piece of CHEESE!
Here is some info from Wikipedia:
The Cooper’s Hill Cheese Rolling and Wake is an annual event held in May at Cooper’s Hill, SO892146, near Cheltenham and Gloucester in the Cotswolds region of England. The event takes its name from the hill it occurs on, a name shared by the village on the hill. Competitors race down the hill after a Double Gloucester cheese, and the first person over the line wins the cheese. In theory, competitors are aiming to catch the cheese, but since it has a one second head start and can reach speeds up to 70 mph (enough to knock over and injure a spectator as it did in 1997), this rarely occurs.
At the very least this looks fun… but painful.