44. All about Mormons (Season 7, Episode 12)
Fuck mormons (j/k).
Still in the same mood from earlier in Season 7 for revisiting US history, Parker and Stone look back to the origins of Mormonism to try and explain why Mormons are the way they are. They more or less succeed, taking the most balanced view an outsider can have about Mormons while still making fun of the circumstances of getting to know them.
In turn, paradoxically, according to Mormons themselves, Mormons who watch this get their belief system re-inforced because all the good things about being Mormon are (apparently) brought to light.