Health Care - S1-E3
Trivia: Creed Bratton plays the voice of the Industrial Coal Mine Shaft employee that Michael talks to on the phone when he's trying to come up with some surprise for the staff. (00:12:15)
Trivia: At around 5 mins 11 seconds into the episode, Vincent Nigel-Murrey and Dr. Saroyan are discussing the bones on the forensic platform. In the background of a shot of Vincent, the x-ray on the screen is of Homer Simpson's head in the middle of the screen, instead of a real human skull.
Trivia: Dr. Spencer Reid is the son of an attorney, born in Las Vegas. In real life, Matthew Gray Gubler, the actor who plays Reid, is also the son of an attorney, born in Las Vegas.
Trivia: The show was filmed in an actual prison (now unused) in Joliet. The death row cell used for Lincoln Burrows is the actual death row cell that held serial killer John Wayne Gacy.
Winning a Battle, Losing the War - S1-E3
Trivia: Several times in this episode, jokes are made about the residents thinking George is gay. Isaiah Washington was later fired for making homophobic remarks about T.R. Knight.
Trees Made of Glass (1) - S1-E1
Trivia: In "Trees Made of Glass, Part 1", Gunneson (William Mapother) is shot in the chest four times by Caffrey. William Mapother previously played Ethan Rom on Lost, who was killed by four shots to the chest.
Trivia: Although they didn't have any scenes together, Kevin McKidd (Vorenus) and Tobias Menzies (Brutus) would discuss their characters and brainstorm about how to portray them, because they felt their characters went through very similar moral conflicts. Confirmed by Kevin McKidd on the season one DVD commentary.
Unraveling - S1-E7
Trivia: Christina is thrown out of her house after the revelation that she's been lying about her life, and leaves town on a Greyhound as the camera pans down to reveal a sign saying "Now leaving Point Pleasant. Please come back soon.". This is almost identical (both the shot of the sign and the story behind it) to the Buffy The Vampire Slayer episode "Becoming" (2x21) - both the show's executive producer (Marti Noxon) and the writer of this episode (Diego Gutierrez) are former BtVS writers.
Trivia: The episode revolves around a man killing people with the same first names as the thirteen apostles (Mary Magdalene being the 13th), and killing them in a similar fashion in which the apostles died. At one point, Colby and David find a box with a mannequin's head in it. This is a reference to the film Se7en, in which seven people are killed for committing one of the seven deadly sins. The film ends with the main characters finding an actual head in a box.
Trivia: In "Four dreams" the alternative Allison who doesn't have children looks at some kids in a restaurant and gets a dreamy look on her face. The mother of the children she is admiring addresses her daughter as "Sofia". The "real" Allison's daughter Ariel is played by actress Sofia Vassilieva.