South Park: Season 6, Episode 13

6 - 13: The Return of the Fellowship of the Ring to the Two Towers

Randy and Sharon give the boys a videotape of Lord of the Rings to take over to Butters, but the tape was accidentally switched with a porno movie, and Butters watches it. The parents send the boys to get the dirty tape back, but everyone seems to want it, including Butters and a group of sixth graders. The boys then undertake an epic quest to return the movie to the video store.