DENVER — Christmas is coming for the nation’s legal marijuana stores.

Well, not just Christmas but also Independence Day and Black Friday and Cyber Monday, all rolled into one smoky celebration known as 420 on Thursday.

“It’s my job to get you high,” yells marijuana store worker Jason Coleman to a crowded house at Medicine Man cannabis dispensary in Denver. The crowd laughs and the line moves slowly forward, with more than 30 people waiting to buy pot. Armed guards check and re-check IDs, and cash flows across the counters.

April 20 has long been a day filled with civil disobedience by marijuana users, who gather in public to light up at 4:20 p.m. The phrase "420" is a longtime code for marijuana users, who work it into dating profiles or post it on signs to show their shared interest. But while it used to be a celebration held with a certain level of furtiveness, the rapidly expanding legalization of cannabis means more and more Americans no longer face significant, if any, punishment for smoking pot.

All states that have legalized medical or recreational marijuana have also banned public consumption, but those rules are often ignored on April 20, when crowds gather on college campuses and central parks to light up. That means big sales days for stores, especially in states with functioning marijuana marketplaces: Colorado, Oregon and Washington, which could see single-day 420 sales of $20 million, said Matt Karnes of GreenWave Advisors.

Medicine Man, one of Colorado’s biggest pot shops, expected to see more than double the normal number of customers each day Tuesday, Wednesday and Thursday. Among the customers were Chicagoans Patrick Olszewski and Savannah Janzen, who came straight from nearby Denver International Airport with their luggage. They planned to attend 420 celebrations while apartment hunting for a planned move to Denver this fall.

“It’s awesome,” says Olszewski, 25. “The feeling of being at ease, of not having to worry, and getting exactly what you want.”

Legalization activists often stage stunts in conjunction with the 420 celebrations.

In Washington, D.C., for example, activists are planning to give out 1,000 marijuana cigarettes to Capitol Hill workers and members of Congress, and then hold a mass “smoke-in” on the Capitol steps Monday. They’re trying to persuade Congress to reauthorize a law banning federal prosecutors from interfering with state-level medical marijuana programs and are also seeking clarity on how the Trump administration will approach voter-approved recreational pot.

While the District of Columbia’s voters have approved recreational marijuana, Congress has banned the district from creating any sort of system to permit taxable sales.

In Washington state, marijuana sales are expected to easily top last year’s volume of $4.8 million from April 20, 2016, according to New Frontier Data, which analyzes cannabis data. And the 2016 numbers themselves represented a staggering 200% increase over 2015. New Frontier said making year-to-year comparisons of marijuana sales is hard because the industry is so young and growing so fast and because people often celebrate 420 on the weekend closest to it, rather than the actual day.

But for many customers, there’s an undeniable attraction to being able to say they bought legal pot for that specific day. In Colorado’s cannabis stores, the demand was obvious Wednesday: lines snaking through lobbies and guards collecting cash as harried workers rushed to complete orders. Many Denver-area hotels are sold out, and cannabis tourists were pouring into the state for free concerts and then a massive rally outside the Statehouse.

Baker, a point-of-sale software service for recreational and medical cannabis dispensaries in 10 states, said pre-rolled joints are among the most popular 420 purchases, with a 221% increase in sales during the 420 period last year over a normal day.

In Nevada, which recently legalized recreational marijuana but still only has medical shops, business was also expected to be brisk.

"In some states, there’s huge lines, but I don’t imagine that we’ll see anything like that," said Curtis Loper, owner of Smokn' Ray's Smoke Shop in Reno and Sparks. "Some places there’s 150 people camping out, but that’s just not Reno." Still, Loper's aid his shop's income leaps 400% on April 20 each year.

In Oakland, Calif, marijuana-infused candy manufacturer Kiva made 60,000 special-edition samples of the company's low-dose Petra mints and plans to hold 55 sampling events around the state this week. And in Tulare County, Calif.'s, only dispensary, Canna Can Help, workers have ordered 1,000 tacos for their planned customer appreciation day this weekend.

Back inside Denver's Medicine Man, first-time cannabis tourists pronounced themselves astounded at the variety and options available. Grams of popular strains were selling for $17 plus tax, and like many stores, Medicine Man was offering 420 specials designed for tourists, including pre-rolled joints.

“Budtenders” like Coleman were also extolling the virtues of other products, including highly concentrated “dabs” or marijuana-infused sex lubricant, his description of which drew nervous titters and more than one skeptical face.

“For people like me, it’s mind blowing,” says Catherine Heelan, 45, who was visiting from Liberty, S.C. “There’s no shame. The stigma and shame is gone here. No one looks down on you.”

Contributing: Jennifer Kane, Reno Gazette-Journal, Sheyanne Romero, Visalia Times-Delta.