Star Wars Day, May 4, celebrates Star Wars created by George Lucas. It is observed by fans of the films. Observance of the holiday spread quickly due to Internet, social media, and grassroots celebrations.
Apocryphally, the reference was first used on May 4, 1979, the day Margaret Thatcher took office as Prime Minister of the United Kingdom. An online news article from the Danish public broadcaster says her political party, the Conservatives, placed a congratulatory advertisement in a paper mis-named The London Evening News, saying "May the Fourth Be with You, Maggie. Congratulations."
The saying was used in a UK Parliament defence debate on May 4th 1994.
In 2011, the first organized celebration of Star Wars Day took place in Toronto, Ontario, Canada at the Toronto Underground Cinema. Produced by Sean Ward and Alice Quinn, festivities included an Original Trilogy Trivia Game Show; a costume contest with celebrity judges; and the web’s best tribute films, mash-ups, parodies, and remixes on the big screen. The second annual edition took place on Friday, May 4, 2012.
Fans (even government officials) have celebrated Star Wars in a variety of ways in social media and on television.
Since 2013, The Walt Disney Company has officially observed the holiday with several Star Wars events and festivities at Disneyland and Walt Disney World. Disney had purchased Lucasfilm including the rights to Star Wars in late 2012.
Minor League baseball teams such as the Toledo Mud Hens and the Durham Bulls have worn special uniforms as part of Star Wars Day promotions.
On Star Wars Day 2015, astronauts in the International Space Station watched Star Wars.
Source: wikipedia.org