I missed the 4/20 special last year, so better make up for that! So let's have a look at the movie credited for creating the "Stoner Comedy" genre: Cheech & Chong's "Up in Smoke." It's the story of two comedians that got popular enough, they were able to toss a bunch of material together and call it a movie. What, you want the plot of the movie? Don't look at me...
Source: Up in Smoke Movie Review - Decker Shado