True story? Well, it's at least the most elaborate..: "According to Steven Hager, editor of High Times, the term 420 originated at San Rafael High School, in 1971, among a group of about a dozen pot-smoking wiseacres who called themselves the Waldos. The term 420 was shorthand for the time of day the group would meet, at the campus statue of Louis Pasteur, to smoke pot. ``Waldo Steve,'' a member of the group who now owns a business in San Francisco, says the Waldos would salute each other in the school hallway and say ``420 Louis!'' The term was one of many invented by the group, but it was the one that caught on. ``It was just a joke, but it came to mean all kinds of things, like `Do you have any?' or `Do I look stoned?' '' he said. ``Parents and teachers wouldn't know what we were talking about.'' The term took root, and flourished, and spread beyond San Rafael with the assistance of the Grateful Dead and their dedicated cohort of pot-smoking fans. The Waldos decided to assert their claim to the history of the term after decades of watching it spread, mutate and be appropriated by commercial interests. The Waldos contacted Hager, and presented him with evidence of 420's history, primarily a collection of postmarked letters from the early '70s with lots of mention of 420. They also started a Web site, waldo420.com. ``We have proof, we were the first,'' Waldo Steve said. ``I mean, it's not like we wrote a book or invented anything. We just came up with a phrase. But it's kind of an honor that this emanated from San Rafael.''"
according to 1st site i found on google
