April 1st: This is the day upon which we are reminded of what we are on the other three-hundred and sixty-four." — Mark Twain
April 1--a day for silly jokes. It's not really a holiday. The history and origin of the day are nebulous.
Many examples of jokes and pranks can be found, such as the time that Taco Bell 'bought' the Liberty Bell and renamed it the Taco Liberty Bell. April Fool!