About National Mad Hatter Day
The Mad Hatter is a character in Lewis Carroll's 1865 book Alice's Adventures in Wonderland and its 1871 sequel Through the Looking-Glass. In the books, he is called the Hatter and was never called the Mad Hatter by Carroll.
Although, during the trial of the Knave of Hearts, the King of Hearts remarks upon the Hatter's headgear, Carroll does not describe the exact style of hat he wears. The character's signature top hat comes from John Tenniel's illustrations for the first edition, in which the character wears a large top hat with a hatband reading "In this style 10/6". This refers to the cost of the hat in shillings and pence.
It is the 10/6 that makes October 6th the date chosen for National Mad Hatter Day.
The day was started in 1986 by a group of computer programmers from the city of Bowler (Colorado), who decided to celebrate a day of silliness by wearing top hats that were inspired by the Tenniel's illustrations of the Hatter.
Since then, it has become a day to wear a hat and indulge in all kinds of silliness.