The license plate on Marge's car reads "7G08," the production code for the Simpsons pilot, Simpsons Roasting on an Open Fire (1989) which also revolved around a holiday.
The first canon Halloween special of the series outside of the annual "Treehouse of Horror" specials it is also the first halloween horror episode to not have "Treehouse" in the episode's title and the first halloween episode to be full length as opposed to three parts.
"NC-17 Halloween," the song featured towards the end of the episode is a parody of "The Time Warp" from the cult classic film The Rocky Horror Picture Show (1975).
Krustyland's horror night is a parody of Universal's Halloween Horror Nights at the theme parks in California and Florida. The E. T. that says kids' names is also a reference to the tie-in ride at Universal Studios.