 In the scene in the video store (the one when Lisa finds out that  Joe has been doing porno films), the first shot shows the top row of  a movie section. Contained in this row are all movies by Troma  Studios. Troma owns the rights to Trey Parker (I) (qv)s first  film, _Alferd Packer: The Musical (1996)_ (qv) (aka Cannibal! The  Musical). Parker has also noted Troma as inspiration for his style  of filmmaking and for _"South Park" (1997)_ (qv).