On Jan. 1, Colorado legalized the recreational use of marijuana. A whole nation of weed smokers, from Texas to New York, lit one up to celebrate the news.

Nick Remaklus, born and raised in Kentucky, was one of them. As soon as he got some time off work, he headed to Denver to check out America's new smokers' oasis. "It was great. I took a wonderful tour and learned so much about the industry," says the 29-year-old. "It just felt great to know I wasn't doing something illegal."

Remaklus is one of the growing number of visitors flocking to Washington and Colorado in search of some once-forbidden grass, creating a brand-new vice tourism industry. Fun for tourists; lucrative source of income for those states.

Tours are popping up in Denver and Seattle, slowly transforming them into cannabis meccas offering everything from good old-fashioned weed sampling to first-class pot cooking classes where visitors can learn to make THC-infused ricotta-stuffed bell peppers.

Local dispensaries have been the first to notice a surge in out-of-state customers. "We've found that upwards of 80 percent of our revenue is coming from bordering states that have not yet legalized recreational marijuana," says Ryan Griego, managing partner at Cannasseur, a recreational dispensary in southern Colorado, just an hour and a half away from the state border. Most visitors are from Texas, Kansas and Utah.

With about 22 million weed-smoking Americans, and only two states offering legal recreational highs, a new wave of "ganjapreneurs" is ready to cash in.

Colorado is starting to feel like an Alpine Amsterdam, with marijuana tours and private cannabis clubs mushrooming all over and attracting tourists from as far as Australia and Singapore.

"It's been very interesting to see the type of people who come to our tours," says JJ Walker, the CEO of My 420 Tours. "I first thought it was going to be a bunch of 20-somethings looking to get high, but most of our clients are actually over 40. Some have been saving for a long time, others have never tried it. ... We even had a terminally ill man recently who came here with his wife."

The tours can be cathartic. "It may have been a tour for most people, but it changed my life," says Remaklus, who decided to quit his job and move to Colorado from Louisville after being shown around by the My 420 Tours crew. "I fell in love with the city, the people and the culture. It's such an exciting time to be here." Now the young sales rep works for another tour company, So Mile High, whose three-day "signature tour" includes a private jet, fine dining, spa treatments and a luxury hotel room for the modest sum of $38,000.

The hotel industry is also jumping on the weed wagon and starting to offer beds to potheads. Since smoking in public is still illegal in both states, a growing list of hotels allow clients to vaporize, smoke or ingest cannabis edibles. Colorado even has its own cannabis-friendly Airbnb-style site, TravelTHC.

So far state authorities have welcomed the new industry, and it's no secret why. Weed sales are taxed at about 10 percent, and Colorado has already collected more than$29.7 million in taxes from recreational marijuana—surpassing taxes on medical sales. Washington is expecting to get $51.2 million in revenue between 2015 and 2017.

Is vice tourism a smart model? If America's experience with gambling tourism says anything, profits might not be sustainable. Lured by the promise of attracting visitors, states rushed to loosen legislation and embarked on a full-blown casino-building frenzy. The glut, however, has led to a saturated market, a fall in customers and casinos having to close their doors. Weed tourism could go down the same path as other states join the party.

Colorado already has to share the tourism spotlight with Washington, the second American recreational pot market, which arrived at the party a little late—retail sales only started in June—but it's picking up speed thanks to a small group of homegrown companies like Cannabus, a 30-foot mobile smokers' lounge.

Weed tourism also raises fears of more local consumption by youngsters and the abuse of edibles—especially after the death of a 19-year-old student from Wyoming who jumped off his hotel balcony in Denver after eating marijuana-infused cookies. The increase of pot-related DUIs is also a serious concern in Washington, though in Colorado, highway fatalities have decreased since the legalization of marijuana.

"Years from now, people will look at us as part of the cultural landscape, as we now do with museums," says the enthusiastic Michael Gordon, CEO of Kush Tourism, a Seattle-based startup offering weed-themed tours and courses in bong glass blowing, hash making and using cannabis as medicine.

Operators in the area, however, got ahead of themselves. "Cannabis tourism will have a problem because the supplies aren't there yet. It's really spotty," says John Davis, executive director of the Coalition for Cannabis Standards & Ethics and CEO of Northwest Patient Resource Center, a medical dispensary in Seattle.

He worries that newcomers will turn to the black market to supply tourists. "It only takes one to tarnish the image of the whole industry," says Davis.

Naysayers also claim pot tourism could hurt the city's image. But Seattle officials don't seemed too worried. "I think we will find that cannabis tourism will not be as strong in Seattle as it is in Colorado due to the fact that Seattle has had relaxed laws for simple possession of marijuana since 2004. We don't have the same newness factor," says Nick Licata, a member of the Seattle City Council.

Next to latch onto weed tourism could be Oregon, Alaska and Washington, D.C., which are keeping an eye on Colorado and Washington state as they wait for citizens to vote on recreational legalization in November.

Weed entrepreneurs have high hopes. "We already have plans to expand to Seattle and maybe Las Vegas," says Walker of My 420 Tours. "We'll soon also have the first pot-friendly hotel in a ski resort!"