From IMDb: Tom's mother discovers a marijuana joint in his room. When his parents confront him, Tom denies being a "dope fiend." Despite his dad's admonitions about the dangers of pot, one of which is "an uncontrollable feeling of hilarity," Tom still doesn't buy it, and decides to find out for himself what pot's effects are. He goes down to where the local "weedheads" hang out and is disgusted by their sloppiness and their laziness. A couple of friendly policemen tell Tom that the reason the weedheads are like that is that pot use results in a "wholesale abandonment of goals and ambitions." While digesting this terrifying prospect, Tom is mugged by a desperate band of marijuana addicts, and finally realizes how right his parents were to try to get him to "keep off the grass!"
[youtube=425,350]http://www.youtube.com/watch?v=UmuLkiZw2lY[/youtube]
Part 1 (Time: 10:16)
[youtube=425,350]http://www.youtube.com/watch?v=fdt4NgYFd6g&feature=related[/youtube]
Part 2 (Time: 10:44)
A viewer comment from Internet Archive: This is great. Imagine showing this to a classroom full of high school students today: they'd laugh you out of the room.