Various urban legends have grown up around the meaning of 420 and its connection to marijuana, but the true story behind it is surprisingly prosaic. In the early 1970s, a small group of hippie stoners at San Rafael High School in California used to meet at a designated location every day at 4:20 p.m. to smoke weed.They did this so regularly that members of the group-who called themselves the Waldos-began using the expression "420" as a euphemism for...