The South Park clip is in the movie, and they work it into the movie in a novel way. Seeing the clip won't ruin the movie for you, as no two tellings of the joke are the same. I still laughed my ass off during the South Park clip, and I'd already seen it a dozen times. The movie is pretty damn funny, I only got a little uneasy once during the film, and that was early on when George Carlin told a version of it. Let's just say that those of you who think of Bob Saget as the square dad on "Full House" are in for a shock if you see this movie.