Numerous references are made to the fact that Frasier hasn't been with a woman since the previous Christmas. This is in fact true, and the woman in question was Kate Costas (Mercedes Ruehl).
In an attempt to impress regular guy author Houghton, Niles tells the tale of Boston Red Sox owner Harry Frazee selling Babe Ruth to the Yankees to finance the popular 20's musical, No No Nannette. This is in fact a sports "urban legend" and had been factually debunked in several works.
Goof: At about three-minutes, John Mahoney (Martin Crane) is too early for a cue and is visible just off camera to the left.
At 17:12 in the episode, Niles enters Frasier's apartment while Martin is on the phone. Standing just to the left of the door is a crew member in gray slacks, almost entirely visible.
During Reggie McLemore's TV interview, you can see a strip of black electrician's tape over the brand name on Frasier's television so that there is no free advertisements on the show.
In the scene at the basketball game, the "S-U-P" in the floor to begin the word "Supersonics" suggests that Niles and company are sitting near the sideline. But there is way too much space between the sideline and the 3-point line for an NBA court. In fact, there's too much space between them for a college court!
Niles acts like he hates doing Frasier's show, but he was having a ball doing it in the episode "Frasier Crane's Day Off".
Ma Nature was one of the shows vying to replace Frasier's show in the episode "Agents in America, Part III". She apparently is the replacement for Father Mike, who was fired in the episode "She's the Boss".
Although necessary for staging purposes, it's unlikely that Daphne would give Rodney the Crane's home phone number when she has a private phone in her room (listed under "Daphne Moon" as we learn from Clive in "The Two Mrs. Cranes").
(Niles has just made a disparaging remark about Lilith)
Frasier: As if a smile from Maris couldn't freeze mercury.
The freezing temperature of mercury is -78°F (-61.1 °C).
When Frasier, Niles and Martin are rushing out to avoid Daphne's cooking, on the left top screen you can see a boom mic visible.
Frasier mentions the smoking jacket he gave Martin for Christmas in episode "Frasier Grinch".
The title of this episode is meant to sound like, "Dad loves sherry, the boys just wine". The irony of it is, the Crane boys, as we well know, just love their sherry, and "dad" loves Balantine.
Martin claims that Hester liked everyone and found something to like in everyone. However, she despised Diane in the Cheers episode "Diane Meets Mom", and still hated her in the Season 9 episode "Don Juan in Hell (2)".
John Rajeski is actually the name of one of the show's producer's assistants. He appears as a Cafe Nervosa waiter in, "You Can Go Home Again".
Frasier tells Niles that he once saw Maris naked in the shower. Since Frasier also saw Daphne in the shower in Season Two's "Daphne's Room", that means he has seen both of Niles' wives naked in the shower. Of course, Niles sleeping with Lilith in Season Five's "Room Service" more-or-less makes up for it.
Niles: (lamenting an opera he's just attended) ...the soprano couldn't hit the E-flat above high-C to save her life.
An operatic soprano's vocal range is from C in the fourth octave (on a piano) to C in the sixth octave (high-C). If she could have hit the E-flat above high-C, she would have been classified as a sopranino, not a soprano.
When Martin asks Niles if he can have a romantic evening with Sherry at Niles' apartment, Martin says Sherry's apartment isn't an option because he's allergic to her cats. However, in "Dad Loves Sherry, the Boys Just Whine," Martin said he and Sherry were spending time at her apartment, and the only problem was that she lived in a fourth floor walk-up which was hard on his hip. He made no mention of her cats.
The book that Martin is reading to Daphne whilst she is sick is none other than The Rose and the Rapier, first mentioned by its author (Deirdre Sauvage) in the Season Three episode "The Adventures of Bad Boy and Dirty Girl (2)".
When Frasier lights the fireplace, if you look to the right of the screen you can see the bird handler's hands giving it the signal to jump to Niles' head.