In the beginning of "Hollywood Babylon," the Winchesters are on a tour of Hollywood. The tour guide says that they are passing the place where Gilmore Girls (2000) is filmed, and if they're lucky they might get to see one of the stars. Jared Padalecki, who plays Sam Winchester, had a starring role on Gilmore Girls (2000), playing a character named Dean Forester. At this point, Sam Winchester looks uncomfortable and quickly leaves the tour bus.
When Dean tells Tara she was great in 'Boogeyman', she says it was a horrible script. The Script to Boogeyman (2005) was written by Supernatural creator Eric Kripke.
The first episode in the series without Dean's Impala.
Some of the notes that the studio executive gives the crew are notes that Supernatural actually received from CW.
When Dean mentions that he wanted to come to California for "swimming pools, movie stars" (lines from the theme song to The Beverly Hillbillies (1962)), Sam replies that it is not swimming pool weather, as it is "practically Canadian". This is in reference to the fact that Supernatural is not filmed in Los Angeles, but in Vancouver, Canada.