Why is APRIL 1 – a day to celebrate foolishness?

Fact #1 : The most popular theory is that France changed its calendar in the 1500s so that the New Year would begin in January to match the Roman calendar instead of beginning at the start of spring, in late March or early April. However, word of the change traveled slowly, and many people in rural areas continued to celebrate the New Year in the spring. These country dwellers(a person or animal that lives in particular place) became known as “April fools,” the story goes. But Boese, who’s studied the holiday’s origin, said the “theory is completely wrong, because the day that the French celebrated the beginning of the year, legally, was Easter day, so it never really was associated with April first. 

Fact #2:  Iranians play jokes on each other on the 13th day of the Persian new year (Norouz), which falls on April 1 or April 2. This day, celebrated as far back as 536 BC , is called Sizdah Bedar and is the oldest prank-tradition in the world still alive today; this fact has led many to believe that April Fools’ Day has its origins in this tradition.
bharathy.inz.cc-April fish

Fact #3: Today in France, people who are fooled on April 1 are called Poisson d’Avril, which literally means the “April Fish.” One common joke is to hook a cardboard fish to the back of a person. What a fish has to do with April Fools’ Day is not clear. Some believe that the fish is tied to Jesus Christ, who was often represented as a fish in early Christian times. Others say the fish is related to the zodiac sign of Pisces, which is represented by a fish, and falls near April. It’s interesting to point out that Napoleon earned the Poisson d’Avril monicker when he married Marie-Louise of Austria on April 1, 1810.

Fact #4: Alabama Changes the Value of Pi: The April 1998 issue of the New Mexicans for Science and Reason newsletter contained an article claiming that the Alabama state legislature had voted to change the value of the mathematical constant pi from 3.14159 to the ‘Biblical value’ of 3.0. Soon the article made its way onto the internet, and then it rapidly spread. It only became apparent how far the article had spread when the Alabama legislature began receiving hundreds of calls from people protesting the legislation.