If you're in the Denver area this weekend, don't be surprised if you get a bit of a contact high.

This weekend, Denver is holding a two-day 420 Rally in support and celebration of marijuana, The LA Times reports.

The rally, which was once an underground event, celebrates Colorado's Amendment 64, which legalized recreational marijuana use when it was signed into law in 2013.

The rally has been held since the 1970s, and describes itself as "a cannabis culture music festival."

However, the rally tows the line of legality; although the law allows people aged 21 and older to smoke pot, smoking in public is still illegal.

The event, which will be held on Friday and Saturday, will feature performances by Wyclef Jean, Rose Quartz and the Expendables, as well as a host of other DJs and bands, as well as many food vendors.

"Our goal is to create a positive environment for users to share stories, learn about the industry and create informed opinions on the remaining issues facing the industry," rally organizer Miguel Lopez said in a statement.

There will be more security at the event this year, as three people were injured when gunfire broke out at the event in Civic Center Park last year.

The 420 Rally website instructs festival-goers to "radiate positivity," share, respect the city park, and speak to vendors about issues surrounding marijuana.

While there will be some who will try to smoke weed in public, the ritual of lighting up at 4:20 p.m. on 4/20 is discouraged.

Pot is still banned federally, so travelers will not be able to bring marijuana onto airplanes. Colorado Springs and Aspen/Pitkin County have set up "amnesty boxes" in terminals so fliers can get rid of marijuana before they board the plane.

Denver International Airport also bans possession of pot in the building.

It is also still illegal to possess or use pot on federal public lands, which includes forests, national parks and monument areas.