From the Mildly Interesting file: Since April is the month of 4/20, we have the perfect Top 10. Here are 10 things you might not know (or might have confused) about 420 and its mythology. 10. We start the list with things that are incorrect: 420 is not a police radio code to denote smoking marijuana in public, as urban legend has told it. 9. The hippy rock band The Grateful Dead didn’t invent 420 either, as they are sometimes credited. They did, however, help spread it. 8. The 420 phenomenon has nothing to do with the birth or death of Bob Marley, Jimi Hendrix, Janis Joplin or Jim Morrison. None of them have a tie to April 20. 7. The term “420†dates back to 1971, and like many trendy things, it started with high-school kids. 6. A group of five friends who called themselves The Waldos from San Rafael High School (near San Francisco) had heard about an abandoned marijuana crop in a nearby forest and wanted to find it. They’d meet at 4:20 p.m. every day for a few weeks to go searching for it. 5. They’d tell each other “420†when they passed in the halls as a reminder of their appointment to meet. 4. Afterward “420†became their inside code for pot smoking, since getting high is what they did while searching for the abandoned crop. 3. Members of The Waldos were close enough to The Grateful Dead that they could visit rehearsals. That’s where, they believe, the term “420†started to spread. 2. Today, smokers everywhere celebrate on April 20. Some of the largest celebrations are at college campuses — thousands upon thousands of people show up, for instance, at University of Colorado at Boulder and University of California-Santa Cruz. 1. The Waldos, the originators of 420, never did find the crop of marijuana they were looking for. But they became stoner legends, and that’s more permanent.