Neil Flynn (Janitor) and Paul Hipp (Marc) also appeared together on the show The Middle as Mike Heck and Reverend TimTom respectively.
The music playing while the Janitor is giving Carla the evil eye is a selection from koyaanisqatsi. This particular excerpt was also used in the episode "My New God".
The original broadcast included a scene were J.D. was in black face. All occurrences of black face have been removed from streaming versions.