The THC Ministry proclaims itself to be a religion that believes that cannabis is a sacrament. In their opinion, cannabis is "the original sacrament of Hebrew, Muslim, Christian, Hindu, Shinto, Buddhist, Rasta and more, and fulfills the prophesies to ‘raise up for them a plant of renown…’". It was founded in 2000, by Rev. Roger Christie of Hawaii. It has branches in Colorado, California and Montana, as well as an Amsterdam THC Ministry, First Universal Church of Kantheism, which is run by Rev. Ferre van Beveren, whose "ancestral shamanic roots go back for thousands of years."
The primary purpose of the ministry appears to be providing a loophole in drug laws, by ordaining members as "practitioners" and thus presenting them with a "defense to prosecution" in terms of (one assumes) US law. Their web site only points to Hawaii's definition of the law, as well as that state's definition of "practitioner." 
For $250, you can purchase a "sanctuary kit", which includes "Sanctuary Plaques, ID Cards, Sacramental Plant tags, THC Minsitry Cannabis and Religion Guide" whatever they may be. They also say "The best religious defense to prosecution for any marijuana charge is based in your own sincerity and in the legitimacy of your religious organization," then add the handy caveat, "The sincerity part is up to you!" However, a Colorado judge saw otherwise, convicted a man who tried to claim cannabis use as a sacrament and fined him $450.
The "THC" of the ministry's name refers to Tetrahydrocannabinol, the active ingredient of cannabis.