Since we’re in the pot capital of the universe, you probably know that yesterday was 4/20. If not, don’t sweat it. 4/20 is all about 4:20pm, the time of day that is ritually observed by those who enjoy marijuana so much that they allow it to define their lifestyle. The every other evening “after the kids go to sleep” tokers could give a shit. Give it a day. Call it a name. Big deal. 4/20 is for the full-on stoners.

For these chronic types 4/20 can be every day, once a week, or whenever they remember, but at 4:20pm on the 20th day of the 4th month, the celebration takes on a mass appeal. Here at home yesterday, thousands of people gathered at the Vancouver Art Gallery to simultaneously spark up at the precise time. The cops took a hands-off approach with the crowds. What else could they do?

“We’re trying to stay upwind,” joked Vancouver police Sgt. Jim Patenaude, who was watching with a number of other officers on bicycles as smoke clouds arose from the crowd.

He said police were mainly monitoring the situation for crowd control and public safety.

“We’re just here to keep the peace,” Patenaude explained.

“It would be totally inappropriate to jump in and arrest.”

Yathink?

Considering the apparent significance of the date, it would be good to know the what and the why of it. I’ve heard plenty of stories over the years, but HuffPo provides some concrete:

Depending on who you ask, or their state of inebriation, there are as many varieties of answers as strains of medical bud in California. It’s the number of active chemicals in marijuana. It’s teatime in Holland. It has something to do with Hitler’s birthday. It’s those numbers in that Bob Dylan song multiplied.

The origin of the term 420, celebrated around the world by pot smokers every April 20th, has long been obscured by the clouded memories of the folks who made it a phenomenon.

The Huffington Post chased the term back to its roots and was able to find it in a lost patch of cannabis in a Point Reyes, California forest. Just as interesting as its origin, it turns out, is how it spread.

It starts with the Dead.

It was Christmas week in Oakland, 1990. Steven Bloom was wandering through The Lot – that timeless gathering of hippies that springs up in the parking lot before every Grateful Dead concert – when a Deadhead handed him a yellow flyer.

“We are going to meet at 4:20 on 4/20 for 420-ing in Marin County at the Bolinas Ridge sunset spot on Mt. Tamalpais,” reads the message, which Bloom dug up and forwarded to the Huffington Post. Bloom, then a reporter for High Times magazine and now the publisher of CelebStoner.com and co-author of Pot Culture, had never heard of “420-ing” before.

The flyer came complete with a 420 back story: “420 started somewhere in San Rafael, California in the late ’70s. It started as the police code for Marijuana Smoking in Progress. After local heads heard of the police call, they started using the expression 420 when referring to herb – Let’s Go 420, dude!”

Bloom reported his find in the May 1991 issue of High Times, which the magazine found in its archives and provided to the Huffington Post. The story, though, was only partially right.

It had nothing to do with a police code — though the San Rafael part was dead on. Indeed, a group of five San Rafael High School friends known as the Waldos – by virtue of their chosen hang-out spot, a wall outside the school – coined the term in 1971. The Huffington Post spoke with Waldo Steve, Waldo Dave and Dave’s older brother, Patrick, and confirmed their full names and identities, which they asked to keep secret for professional reasons.

The Waldos never envisioned that pot smokers the world over would celebrate each April 20th as a result of their foray into the Point Reyes forest. The day has managed to become something of a national holiday in the face of official condemnation. This year’s celebration will be no different. Officials at the University of Colorado at Boulder and University of California, Santa Cruz, which boast two of the biggest smoke outs, are pushing back. “As another April 20 approaches, we are faced with concerns from students, parents, alumni, Regents, and community members about a repeat of last year’s 4/20 ‘event,'” wrote Boulder’s chancellor in a letter to students. “On April 20, 2009, we hope that you will choose not to participate in unlawful activity that debases the reputation of your University and degree, and will encourage your fellow Buffs to act with pride and remember who they really are.”

But the Cheshire cat is out of the bag. Students and locals will show up at round four, light up at 4:20 and be gone shortly thereafter. No bands, no speakers, no chants. Just a bunch of people getting together and getting stoned.

The code often creeps into popular culture and mainstream settings. All of the clocks in Pulp Fiction, for instance, are set to 4:20. In 2003, when the California legislature codified the medical marijuana law voters had approved, the bill was named SB420.

“We think it was a staffer working for [lead Assembly sponsor Mark] Leno, but no one has ever fessed up,” says Steph Sherer, head of Americans for Safe Access, which lobbied on behalf of the bill. California legislative staffers spoken to for this story say that the 420 designation remains a mystery, but that both Leno and the lead Senate sponsor, John Vasconcellos, are hip enough that they must have known what it meant. (If you were involved with SB420 and know the story, email me.)

The code pops up in Craig’s List postings when fellow smokers search for “420 friendly” roommates. “It’s just a vaguer way of saying it and it kind of makes it kind of cool,” says Bloom. “Like, you know you’re in the know, but that does show you how it’s in the mainstream.”

The Waldos do have proof, however, that they used the term in the early ’70s in the form of an old 420 flag and numerous letters with 420 references and early ’70s post marks. They also have a story.

It goes like this: One day in the Fall of 1971 – harvest time – the Waldos got word of a Coast Guard service member who could no longer tend his plot of marijuana plants near the Point Reyes Peninsula Coast Guard station. A treasure map in hand, the Waldos decided to pluck some of this free bud.

The Waldos were all athletes and agreed to meet at the statue of Loius Pasteur outside the school at 4:20, after practice, to begin the hunt.

“We would remind each other in the hallways we were supposed to meet up at 4:20. It originally started out 4:20-Louis and we eventually dropped the Louis,” Waldo Steve tells the Huffington Post.

The first forays out were unsuccessful, but the group kept looking for the hidden crop. “We’d meet at 4:20 and get in my old ’66 Chevy Impala and, of course, we’d smoke instantly and smoke all the way out to Pt. Reyes and smoke the entire time we were out there. We did it week after week,” says Steve. “We never actually found the patch.”

But they did find a useful codeword. “I could say to one of my friends, I’d go, 420, and it was telepathic. He would know if I was saying, ‘Hey, do you wanna go smoke some?’ Or, ‘Do you have any?’ Or, ‘Are you stoned right now?’ It was kind of telepathic just from the way you said it,” Steve says. “Our teachers didn’t know what we were talking about. Our parents didn’t know what we were talking about.”

They do now.