Slate's first episode of Season 5 is all about Stag Films. Stag films were those seedy, grimy one reel films that were made in the 20s, 30s, 40s and 50s that featured things you couldn't see in any theater in America: SEX. But how did they start and where did they come from? And how did they influence porn features in the 70s, home video in the 80s and internet porn of today?