For a certain sect, the 20th of April is an important national holiday. Some even take the day off in order to ensure that they’re available to commemorate the holiday’s main ritual, which, naturally, takes place at precisely 4:20 p.m.
Though the history of this heady day—like so many other counterculture references—is a bit murky, legend has it that the phrase “420” was originally police code for “Marijuana Smoking in Progress.” Other rumors state that it all started (where else?) in a parking lot before a Grateful Dead show.