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: When Ted and Robin are at the restaurant, they are accidentally sent a champagne glass with an engagement ring in. A man then claims the ring and proposes to his girlfriend. This couple really did get engaged on the show - the guy set up the surprise proposal, as his girlfriend thought they were just there as extras.
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.
Trivia: Maddy starts to film her movie and Mr. Mosby tells her that he is ready. Look at what he does right before she starts filming. He chants "Mah, mah, mah" and does the same thing Ashley Tisdale does in "High School Musical" before performing.
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.
Teacher Earl - S1-E5
Trivia: One of the lamps stolen by Ralph is the 'special prize' leg lamp won by the father in A Christmas Story (1983).
Back With a Vengeance - S2-E13
Trivia: About all of the aliens found in attendance of Kevin's mega cruiser strangely resemble those individuals previously seen (on the selfsame ship) in episode 2-5, "Grudge Match", whereas they should have escaped the cruiser near the end of that episode.
Trivia: In the show, there's a running gag of Charlie being obsessed with the waitress and her constantly rejecting him. In real life Charlie (Charlie Day) and the waitress (Mary Elizabeth Ellis) are married. They married in 2006, although they were dating before the show started.
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.
The Library - S2-E10
Trivia: Wan Shi Tong is of one the few things in this show that is not a reference to Asian cultures, but to Ancient Greece instead. In their mythology owls were the symbol of wisdom and their goddess of wisdom, Athena, was often depicted with an owl.
Deacon Stan, Jesus Man - S1-E8
Trivia: Chuck White's number plate reads A113. This is a reference often used by alumni of California Institute of the Arts, referring to the classroom number used by animation students there. (00:01:30)