MacQuarrie and his alias Garth Longmore were named after the show's second camera assistants.
Hidden Pineapple location: The pineapple was on the doormat at Shawn's apartment! (per the USA Network website, not able to be seen on screen)
The portrait of Shawn from season 2, Episode 14 (Dis-Lodged) is now located in Shawn's apartment.
In Shawn's home there is an American Werewolf in London poster on his wall. There were a number of references to this film in the episode before this one "Let's Get Hairy".
Gus says that "Mentalist spoilers" was in Shawn's search history. The Mentalist (2008) is TV series about a fake psychic who becomes a detective.