A little history for you…
April Fool’s Day, the first of April, also known as All Fools’ Day. On this day practical jokes are played, such as sending a friend on a fool’s errand or duping him into doing or believing something absurd.
Although the practices of the day are of obscure origin, they are thought to have arisen with the celebrations of the vernal (spring) equinox. Many folklorists believe that the custom of playing someone for a fool on this day was begun in France in 1564 with the adoption of the reformed calendar. A person who resisted changing New Year’s Day from April 1 to January 1 was victimized by pranksters on April 1 and became known as poisson d’avril (April fish).
Widespread observance of the day began in England in the 18th century. In Scotland, the custom of making April fools is known as hunting the gowk (cuckoo). In Mexico, All Fools’ Day is celebrated on December 28.
“April Fool’s Day.” Encyclopedia Americana. 2010. Grolier Online. 1 Apr. 2010 <http://ea.grolier.com/article?id=0018900-00>