From Wikipedia (April Fool’s Day):
April Fools’ Day is celebrated all around the world on the 1st of April of every year. Sometimes referred to as All Fools’ Day, April 1 is not a legal holiday, but is widely recognized and celebrated as a day that tolerates practical jokes and general foolishness. The day is marked by the commission of good humoured or funny jokes, hoaxes, and other practical jokes of varying sophistication on friends, family members, teachers, neighbors, work associates, etc.
Traditionally, in some countries such as New Zealand,Ireland, the UK, Australia, and South Africa, the jokes only last until noon, and someone who plays a trick after noon is called an “April Fool”. It is for this reason that newspapers in the U.K. that run a front page April fool only do so on the first (morning) edition. Elsewhere, such as in France, Italy, South Korea, Japan, Russia, The Netherlands, Germany, Brazil, Canada, and the U.S., the jokes last all day. The earliest recorded association between 1st April and foolishness can be found in Chaucer’s Canterbury Tales (1392). Many writers suggest that the restoration of the 1st of January as New Year’s Day in the 16th century was responsible for the creation of the holiday, but this theory does not explain earlier references.
What’s the best April Fool’s Day joke you ever played?