In one Halloween episode, Frank dresses up like Frankenstein's monster (with Marie as his bride). At first this just seems like a quick gag on Frank's name until you remember Peter Boyle played the monster in the hysterically funny parody Young Frankenstein.
In "Six Feet Under," Boyle recites his "one guy dies, another guy gets well" speech from Taxi Driver almost verbatim. Unlike Travis Bickle, Ray doesn't appreciate the advice: "What the hell are you talking about?"
Ray's crossover on The Nanny at his, Fran Fine's, and Val Toriello's high school reunion. Truth in Television, as actors Ray Romano and Fran Drescher really did attend Hillcrest High School in Queens, NYC in the same class.
One episode had J.G. Hertzler play an old book author who, while rambling on at a bookstore, causes Ray to fall asleep. He happens to be missing an eye...
Frank defends his staying to watch Ray's housekeeper clean a glass after rejecting her offer to have an affair, saying "I'm not a monk." Peter Boyle did study to become a monk before going into acting instead.
Banned In The United Kingdom: "Marie's Sculpture" has never been screened on British TV because the episode involves Marie making a large sculpture of a vagina, much to the rest of the family's disgust (erect male genitalia and exposed female genitalia are no-no's on UK screens). The explicit nature of Marie's abstract artwork and the fact it is on prominent display throughout the show probably called for the decision; it can't have helped that the series aired before the watershed on Comedy Central and way before the watershed (in the mornings, in fact) on Channel 4. Ironically, US audiences didn't seem to have a problem with it.
The Cast Showoff: Patricia Heaton and Brad Garrett have showed off their singing abilities from time to time, Robert even lampshaded this by saying that in chorus he originally was going to be a "basso profundo" (although most school choruses aren't that specific beyond soprano and alto for girls and tenor and bass for boys).
They only had occasional guest appearances, but Ray Romano's father Albert and Phil Rosenthal's father Max appeared sporadically as friends of Frank named "Max and Albert".
Comedian Andy Kindler played one of Ray's best friends, Andy.
Kevin James originally played a guest character named Kevin, until he got the spinoff The King of Queens, after which his character on "Raymond" was retconned into being Doug Heffernan, just like on "Queens."
Edited for Syndication: As with most any show, certain lines are removed to make room for commercials. In one case, however, it makes a joke even funnier; in the full version of "Counseling", the scene with Bernie and Linda talking about their marriage counseling ends and the next scene is Ray and Debra in the bedroom discussing Bernie and Linda before Debra declares, "We're going to counseling." In the syndicated version, the bedroom scene immediately starts with "We're going to counseling", making it into something of a Gilligan Cut.
Friday Night Death Slot: The show originally aired on Friday nights, but after the first season, it was moved to Monday nights, where it stayed for the remainder of its run.
Keep Circulating the Tapes: "Robert's Wedding" features a scene where Gianni enters the men's bathroom at the church but is uncomfortable about taking a leak since Marie is standing there talking to Robert. Despite Marie telling him to go ahead and pee, Gianni says, "I don't have to go anymore!" and leaves. This scene is strangely absent on the season 7 DVD set, and because of this, Ray's line later in the scene ("Out, ma. You've already got Gianni looking for a fire hydrant") makes no sense.
The Other Darrin: Amy's brother was initially played by Paul Reubens. When the character returned, he had a different name and actor, but was clearly meant to be the same comic book store owner that grew attached to Ray. Off screen, Reubens was arrested on public indecency charges, and although he managed to stay out of jail, Ray Romano didn't like the idea of bringing him back and requested that the character be recast. Oddly, not only was the character recast, but renamed (Russell to Peter)
Nemo was originally played by Joseph V. Perry, but the actor died in February 2000; his character was subsequently played by Robert Ruth in "What Good Are You?" and "Stefania Arrives".
Post-Script Season: The series was originally intended to be only eight seasons long, but Ray Romano and Phil Rosenthal decided to give one last season to the fans. As a result, the final season was a bit shorter than the previous ones.
Not only are Geoffrey and Michael's actors twin brothers in real life, but the actress who plays their sister, Ally, on the show is also their sister in real life.
Bill Parker, the handsome father of Ally's classmate played by David Hunt, is Patricia Heaton's real life husband. Also Frank's lodge buddy Albert, played by Ray's real life dad Albert Romano.
Amy is Phil Rosenthal's real life wife.
Real Life Writes the Plot: According to IMDb, the reason for the recast for Amy's brother was that after his cameo appearance, Reubens was arrested on child pornography charges. This caused Ray Romano to object to him being part of the show's cast.
Separated-at-Birth Casting: Fred Stoller as Cousin Gerard. Lampshaded in "Cousin Gerard", when much to his horror, Ray realises that he looks like, sounds like and apparently is just as annoying as Gerard is.