April Fools' Day, or All Fools' Day, is the first day of April. In many countries, including the United States, it is the custom on this day to play tricks on people. A favorite joke is to send someone on a fool's errand, a search for something that does not exist. In the United States, the victim is called an April Fool.

No one knows where the April Fools' custom began. But some historians believe it may have started in France. There, the old New Year's festival was observed from March 25 to April 1 and ended with an exchange of gifts. In the mid-1560's, King Charles IX changed the New Year to January 1. People who still celebrated the New Year in April were called April fish and sent mock presents. April Fools' Day may be related to the ancient Roman spring festival Hilaria, which celebrates the resurrection of the god Attis.

Holidays are celebrated for all sorts of reasons. Some honor heroes, others commemorate religious events, but April 1 stands out as the only holiday that celebrates foolishness. April Fools' Day, or All Fools Day, is an odd celebration with a strange history. What other holiday asks us to play tricks and dupe our unsuspecting friends and acquaintances?

On April Fools Day we expect to fall for the practical jokes, hoaxes and pranks, the one holiday of the year we should be expecting shenanigans. April fools come in various kinds, sizes, colors and ethnicities. We're big and small and fat and slim and yes even smart most of the time. But this one holiday a year we can be caught off-guard.

Traditionally, this day is an opportunity for playing jokes or tricks on one another. The stranger and the more absurd the better. The challenge is to carry out a trick that is believable, if only for a little while. Tricks are most successful if played earlier in the day before a person is wise to what is going on. Younger children are also more gullible.