Scott Patterson, who plays Luke, was not originally hired to be a series regular. He was only signed on for the pilot episode, but it was only after the discovery of the undeniable chemistry between him and Lauren Graham that he was contracted for more episodes, and quickly became a series regular.
Luke's character was originally written to be played by a woman, but the producers figured that "there wasn't enough testosterone" in the series and that resulted in Scott Patterson turning the character around.
Due to the fast pace speech in the show, the average script for an episode of the show runs 75-80 pages, as opposed to 45-50 for a standard hour-long television show. During the 101st episode, a black and white movie from the 1930s is being shown. Lorelai looks at the movie and says they "talked fast" in those movies.
Rory occasionally speaks Spanish with Ezsperanza, where she's shown to be moderately-fluent, using basic conversational phrases. Ironically, Alexis Bledel is Hispanic (of Argentinian descent) and speaks Spanish fluently, having grown up in a Spanish-speaking household. Bledel has stated that her second language was English and she did not learn it until she attended school.
Milo Ventimiglia was originally supposed to make only a few guest appearances as Jess, Luke's nephew. The producers liked him so much they offered him a 6 season contract as a series regular. He asked to be signed for only 2 years.
When the character Brad Langford (Adam Wylie) returns to Chilton Academy after an absence of several months, he explains that he was away playing Jack in "Into the Woods" on Broadway. Wylie really was away from the series to play Jack in the 2002 Broadway revival of "Into the Woods".
Logan's very wealthy family runs a venerable publishing empire. Their last name, Huntzberger, is a reference to the Sulzberger family, who have owned The New York Times since Arthur Hays Sulzberger succeeded his father-in-law Adolph S. Ochs as publisher in 1935.
The entire town of Stars Hollow is the Warner Bros Studios backlot set called "Midwest Street" built in 1946 for the film Saratoga Trunk (1945) (a small section usually unseen on the show - behind the church - was added in the early 1990's for no particular television or film project). The residential street attached is called Kings Row and was built in 1941 (predating the town set) for the Ronald Reagan film of the same name. No new structures have been added to the backlot for the "Gilmore Girls," although the backlot set remains dressed for the show throughout the television shooting season (July through March or April).
In the season 5 opener "Say Goodbye to Daisy Miller", when Luke is leaving Lorelai messages on her answering machine, he states his phone number is (860) 294-1986. This number was used as a bid for donations toward the new Children's and Maternal Hospital at Hopkins to which the number belongs. Luke is played by Children's Center Director George Dover's brother-in-law, Scott Patterson.
During a June 2015 cast reunion on "The Today Show," Alexis Bledel was asked if she thought Rory would now be with Dean, Jess, or Logan, and her answer was "none of the above": "I think she'd be seeing someone new, or she'd be single and focused on her career. I don't think she'd be married." Lauren Graham then interjected, "that's the best answer ever!"
The character of Jess (played by Milo Ventimiglia) was supposed to have a spin-off called "Windward Circle" which was picked up by the WB for midseason 2004, in which the character moves in with his estranged father (played by Rob Estes) and his father's girlfriend (played by Sherilyn Fenn) from Connecticut to California. But due to the high cost of filming on location in Venice, California, the WB changed their minds and decided not to go forward with it.
Sean Gunn, who plays Kirk, made his first appearance in episode 1.2 ("The Lorelais' First Day at Chilton"), but not as Kirk. His character was named "Mick" and he was installing a DSL server at the Lorelais' home that was ordered by Emily.
Creator Amy Sherman-Palladino originally wanted Sherilyn Fenn to audition for the role of Lorelai Gilmore but she was appearing in _Rude Awakening (1998)_ at the time. Fenn later guest starred as Sasha, Jess' father's girlfriend and then played the recurring character Anna Nardini.
In the episode, "Lorelai's Graduation Day", we discover that Lorelai's middle name is Victoria. Rory's given first name is also Lorelai, but her middle name is Leigh. "Lorelei Lee" is the name of a main character in "Gentleman Prefer Blondes" (played by Carol Channing in the original Broadway production and by Marilyn Monroe in the movie version).
The exterior shots of the girls' home and the foyer and hallway are all filmed on the outdoor set, while nearly all of the interior house scenes are filmed across the studio front lot in a sound stage, where the entire first floor of the home is built to scale.
Lorelai and Christopher are driving to Friday night dinner at the Gilmores. During the drive they are listening to Skid Row's "18 and Life". The lead singer of Skid Row is Sebastian Bach who is Gil the guitarist of Lane's band Hep Alien.
Sherilyn Fenn was to have starred alongside Milo Ventimiglia and Rob Estes in the California-set spin-off "Windward Circle". After The WB dropped the project, "Gilmore Girls" creator Amy Sherman-Palladino wanted to work with Fenn again and wrote the character of Anna Nardini with Fenn in mind, in order to bring her back in the series. The character of Anna was originally to have a strong enough presence to be a potential threat to the character of Lorelai. However, after Sherman left the show, the producers changed the direction originally intended for the character, as they decided to make her a villain in a custody battle.
The exterior "Midwest" sets, which incorporate Stars Hollows' town square, the Gazebo, Luke's Diner and Doosey's Market, are also featured prominently in The Dukes of Hazzard (1979). They can also be seen in a scene in the original theatrical version of The Music Man (1962). There are several subtle references to this fact, including in season 7, Rory's friend referring to Stars Hallow as the perfect small town where "you expect Harry Hill to come to town and con people into buying band instruments" and in season 1, episode 14 in Luke's when Taylor says, "We've got trouble my friends," to which Lorelai responds with, "Right here in River City."
At the end of season 3 in the episode "Say Goodnight, Gracie" Fran Weston's passes away and at the funeral Melissa McCarthy's future husband Ben Falcone plays the role of Mr. Brink and a pallbearer in the procession.
The number of years that Richard and Emily have been married changes. In S2E3 it's 34yrs, S5E13 it's been 40yrs. In episode 18 of season 2 they have been married 35yrs, that's also how long Richard has been in the business world, yet in episode 6 he tells Dean 30 years.
Seasons 4-7 were filmed and aired in HD widescreen. The DVDs were released in the cropped full screen format however, reportedly because Amy Sherman-Palladino didn't like widescreen. When the reruns air on HD networks they can be seen in widescreen, and in 2010 the 16:9 versions were put on iTunes.
At one point Jason (Chris Eigeman) sarcastically states that he's a hologram. Eigeman played Arnold Rimmer in the first pilot of the ill-fated Red Dwarf (1992) (a version of the British sit-com Red Dwarf (1988)). The character of Rimmer is a hologram.
In season 2 episode 3 "Red Light on the Wedding Night" at breakfast with Max they are first brought 3 red coffee mugs, the mugs then change to blue when Lukes walks away, and back to red agian when Max is looking over the menu.
The trivia items below may give away important plot points.
Lane's boyfriend, Dave (Adam Brody), left the show after his first season. To explain his absence, Lane claims that he went to university in California. Brody left the show in order to play the part of Seth in The O.C. (2003), which takes place in California. Also, when Chad Michael Murray (playing Rory's Chilton classmate, Tristin Dugray) left the show, his absence was explained by the character being sent to military school in North Carolina, which is where Murray filmed his recurring role on "Dawson's Creek" and later "One Tree Hill".
Alex Borstein, who was originally cast to play Sookie, has many appearances, including Drella, the Harp player at the Independence Inn; and Miss Celine, who is in the season 5 episode "Come Home". Borstein is married to Jackson Douglas, who played Jackson Belleville on the show; during the run of the series, the characters of Sookie and Jackson eventually fell in love and got married.
Daniel Palladino, series writer, producer, and husband to creator Amy Sherman-Palladino, made an appearance on the pilot of the show. He can be seen in the first scene in Luke's Diner as he walks behind Lorelai to leave the shop.