As the pot smokers' holiday known as 4/20 has transformed into a mainstream event, cannabis companies are anxiously preparing for the hoards of tourists coming to Colorado to indulge legally. Hotels are booked solid across the city between now and April 20, High Times's Cannabis Cup sold out of its 50,000 tickets, and the 4/20 Rally in Civic Center Park is expected to attract 200,000 people.

Last year, Colorado's Department of Tax Revenue collected $5.3 million in marijuana taxes for the month of April, a 1,300 percent increase from 2013. While tourism officials are remaining tight-lipped about the number of visitors and their economic impact this year, it's safe to say tens of thousands of people will be coming to Denver from out of state to celebrate recreational cannabis legalization. Here's a look at some of the event's highlights and the commerce that will surround them.

Dispensaries fill their shelves

As marijuana dispensaries prepare for lines around the block, Blue Line Protection Group, an armed transportation and third-party financial compliance company in Denver, is making sure those shelves are full. Blue Line, which brings product from their clients' grow houses to their dispensaries and then transports the proceeds to the tax office and secure vaults, says they have delivered four times as much cannabis as normal to prepare for the weekend.

According to Michael Jerome, vice president of media and public relations for Blue Line, the company will be making 25 trips for clients on Friday, April 17, each time transporting as much as 30 pounds of pot. All 90 of its employees, most of them armed security operators, also will be on hand to protect dispensaries, grow houses, and events like the Cannabis Cup.

Weed tourism

Colorado Cannabis Tours founder Michael Eymer says his company helped fill hotels with more than 1,000 tourists, adding that he knew of only 50 hotel rooms still vacant at the end of March. Eymer says he has already booked tour bus trips, which will be running every day between April 17 and April 20, for close to 300 guests. The company's April 18 VIP package includes spending time with comedy icon and famous toker Tommy Chong.