Shrovetide is the English equivalent of what is known in the greater part of Southern Europe as the "Carnival", a word which, in spite of wild suggestions to the contrary, is undoubtedly to be derived from the "taking away of flesh" (camera levare) which marked the beginning of Lent.More about Shrovetide from the Catholic Encyclopedia
BBC Religion & Ethics: Shrove Tuesday
James Kiefer's Shrove Tuesday Page
All that drinking, eating, and partying in the streets originally came from an effort to rid your house of meat, milk, eggs, and the other rich foods you were forbidden to eat during Lent but which would spoil if left until Easter. In England, this meant the cooking and eating of pancakes, and there the holiday is usually referred to as "Pancake Day."
Woodlands Junior School's Web Page about "Pancake Day"
Elaine's Pancake Day Page
Domestic-Church.com's Pancake Day Page
The most interesting custom to come out of Shrove Tuesday were the pancake races. One, in Olney, England, has become world famous.
No one is quite certain how the world famous Pancake Race at Olney originated. One story tells us of a harassed housewife, hearing the shriving bell, dashing off to the Church still clutching her frying pan containing a pancake. Another that the gift of pancakes may have been a form of bribe to the Ringer, or Sexton that he might ring the bell sooner; for the ringing of the Church bell was the signal for the beginning of the day's holiday...[Olney Pancake Day Site]Read more about the Olney races.
In 1950 the race became an international event. A challenge was received from the town of Liberal in Kansas, USA, where they had, after seeing press photographs of the race at Olney, conceived the idea of starting a similar custom. Olney readily accepted the challenge and, in a spirit of international goodwill and friendship, the two towns now compete annually and prizes are exchanged....[Olney Pancake Day Site]More info from the city of Liberal and the International Pancake Day site.