The title is based on the play "The Man Who Came to Dinner" written by Moss Hart and George S. Kaufman and opened on Broadway at the Music Box Theatre on October 16, 1939 and ran for 739 performances. The play concerns an acerbic radio-commentator who spends Christmas with a Midwest family after he slips on ice outside their home and injures his hip.
Niles (David Hyde Pierce) commented near the end of the episode that he would never see Maris again. Since Maris was never cast, viewers never saw Maris at all during the Frasier series.
When Ann mentions that her ex still lives in a van it harkens back to Julia Sweeney's time on Saturday Night Live with Chris Farley. One of Chris Farley's top reoccurring skits was a Matt Foley who was a motivational speaker who "lived in a van down by the river."
The police officer in the last scene was played by John Kapelos, who became well known to Gen-Xers as Carl the janitor in "The Breakfast Club".