Vee uses The Farmer and the Viper to warn Gloria about Red, which Janeway was on the receiving end of in an especially memorable Voyager episode.
In an early episode, Maria Dizzia's character Polly includes the secret ingredient of blueberries in her soap, which is one of the things that makes Piper so excited about going into business. This may be a subtle allusion to Dizzia's character Dolores on Louie, who has a penchant for blueberries.
Alex and Piper are called into Healy's office after Pennsatucky trapped Alex in the laundry dryer; Healy's only concern is whether they've been using the dryer for lascivious purposes. Alex responds, "I'm more of a dishwasher kind of gal, sir." This is an allusion to Donna Pinciotti, the character Laura Prepon played on That '70s Show, who mentioned being aroused by dishwashers.
Between him referring to the "webcam incident" and the "penis-shaving horror" in the first episode and the scene with him attempting to "edge," the show doesn't shy away from references to Jason Biggs' breakout role in American Pie.
Nicky refers to Gina as "Squirrel." This could be a reference to Abigail Savage's role as Bunny.
Norma is revealed to have been the loyal wife of a guru/cult leader in the 1970's. This could be a reference to the fact that Annie Golden originated the role of Lynette "Squeaky" Fromme in the musical Assassins.
Suzanne speaks glowingly of the character of Glinda the Good Witch in The Wiz (albeit confusing that version with The Wizard of Oz). In December 2015, Uzo Aduba played that very role in NBC's live televised performance of The Wiz.
Actor-Shared Background: Both Nicky and Natasha Lyonne are estranged from their mothers and have had issues with substance dependency. Also, Lyonne actually did have a heart infection; the scar is real.
Billing Displacement: In a move completely unprecedented for television, Michael J. Harney is credited in every episode of Season 5, but Healy does not appear in any capacity or even get mentioned at any point during the season. It's currently unclear whether his credit was left in by mistake, or whether Healy actually was supposed to appear but had his scenes cut.
The Cast Show Off: The Christmas pageant was an excuse to show off all the talents the actresses had. Including the normally silent Norma, played by the lead singer of the punk band The Shirts.
Creator Backlash: Jenji Kohan has actually gone on record apologising to fans for the quality of Season 5, saying that the writing was often amateurish and the sort of thing you'd expect to see in fan fiction, as well as revealing that she had subsequently fired nearly all of the writing staff who worked on the season.
Dawson Casting: Many of the actresses play their younger, even teenage versions in flashbacks. Some, like Samira Wiley (Poussey) or Emma Myles (Leanne), are more convincing, some, like Taryn Manning (Pennsatucky) less. Also Daya, a character in her early twenties, is played by an actress in her early thirties (and very close in age to the actress playing her on-screen mother), Dascha Polanco, admittedly a definite Older Than They Look case.
Fake American: Brooklyn-Italian Lorna Morello is played by Australian Yael Stone.
Fake Russian: Galina "Red" Reznikov is played by the Irish-American Kate Mulgrew.
Fan Nickname: "Straight Larry" for Larry, after an old joke post on Tumblr about a hypothetical show that inverts the "hilarious token gay" trope with a "hilarious token straight" character by that name.
I Am Not Spock: A few interviewers have made the mistake of equating the personalities of some of the actresses with those of the characters they play. Danielle Brooks and Samira Wiley have gotten it more than once; in reality, both are educated, well-spoken and professional women. However, confusions such as this only speak to the quality of the show's performances.
Killer App: One of the reasons to get a Netflix account if you don't have one already.
Making Use of the Twin: Laverne Cox's (Sophia) twin brother was used to portray her before her transition from male to female. The show runners actually didn't know she had a twin when they cast her, and couldn't believe their luck when they found out.
Separated-at-Birth Casting: Most of the actors playing the younger characters in their flashback episodes pass off fairly well, but especially Kristin Parker as the young Norma stands out.
Star-Making Role: For most of the main cast...except for Kate Mulgrew, Natasha Lyonne, Jason Biggs, Laura Prepon, Lori Petty, and Blair Brown; in their cases, it is Career Resurrection — today, only Biggs is still more associated with his earlier work than with Orange.
Tom Hanks Syndrome: Laura Prepon was previously best known as Donna on That '70s Show, a comedic series that couldn't be any more different than Orange. Today, Donna is essentially as big a footnote in Prepon's career as Hal has become for Bryan Cranston's after Breaking Bad began. Yoga Jones once voiced Patti Mayonnaise on Doug, and her casting as Yoga is what some would call WTH, Casting Agency? at it's best.
What Could Have Been: Uzo Aduba originally auditioned for the part of Watson. Watson was also intended to be the most prominent character of the black group, but gradually became the least prominent one.