When John Mahoney makes fun of Daphne's Manchester accent he's actually doing his original accent. He was born in Blackpool and grew up in Manchester and that's how he would have spoken before he moved to America.
Frasier's piano player in the final scene is played by Murphy "Murph" Dunne, keyboardist for The Blues Brothers Band.
The aria Frasier (Kelsey Grammer) would have attempted was: RIGOLETTO, ACT III - ella mi fu rapita!...parmi veder le lagrime.
The plot revolves in part around Leap Years Day (February 29). The episode originally aired two days before Leap Years Day.