We've given you the history of 420, or 4:20, before, but here, since it's a holiday, is an animated refresher, via Laughing Squid. And yes, it really did all start with a group of stoner teens in San Rafael who met up at 4:20 p.m. every day.
Previously: The Real Dope Behind 420 (Which Was Coined By A Group Of California Teens)