Since the recent vote to fully legalize recreational marijuana, High Times has hosted the Cannabis Cup at the Denver Mart for 3 days around the most important holiday in stonderdom, 4/20. This is the world's premier cannabis festival, which promotes the political legitimacy of pot and marijuana-related education as well as hedonistic good times.
Amsterdam hosted the first years of the cup, but Denver is the flagship location stateside. The world's best growers gather here in an effort to receive honors for the quality of their product, so if you indulge there are sure to be a few strains you'll enjoy and haven't yet encountered. There are also concerts, lectures and other events.
If you've never smoked marijuana, this event may be an overwhelming introduction. Denver has plenty of dispensaries that can ease you in more gently.