April Fool's Day  
   
  April Fools' Day or All Fools' Day is a day celebrated in many countries on April 1. The day is marked by the commission of hoaxes and other practical jokes of varying sophistication on friends, family members, enemies, and neighbors, or sending them on a  
   
  The origin of April Fools' Day is obscure. One likely theory is that the modern holiday was first celebrated soon after the adoption of the Gregorian Calendar; the term referred to someone still adhering to the Julian Calendar, which it replaced.[2] In ma