Bon  420 a tous,   aujourdhui  nous somme le  20 du 4.....    le 420 !!!!  toute la journée

wikipedia :

One explanation of the origin of the term stems from a story about a group of teenagers at San Rafael High School in San Rafael, California, United States in 1971. The teens would meet after school at 4:20 p.m. to smoke marijuana at the Louis Pasteur statue. The exact time was chosen because that was the time that afternoon detention was dismissed.

By extension April 20 ("4/20" in U.S. date notation) has evolved into a counterculture holiday, where people gather to celebrate and consume cannabis.^[1] In some locations this celebration coincides with Earth Week.^[2][3][4] A large celebration is held every year on the University of Colorado's Boulder campus, with attendance reaching more than 10,000 in 2008.^[5] University police have tried various methods to prevent the gathering, including photographing students participating in the event,^[6] but the crowd has grown every year.^[5] In Dunedin, New Zealand, students at the University of Otago and other cannabis law reform activists meet under a walnut tree on the Otago University Union Lawn on Wednesdays and Fridays at 4:20pm to openly smoke cannabis in public in what they consider an act of protest. In 2008 a member of the Dunedin group was arrested and others were issued trespass notices after attempting to openly smoke cannabis at one of the regular 4:20pm protest meetings.^[7][8]