Creator Joel Surnow is a major contributor to conservative causes and political candidates, and the show definitely represents a conservative, ends-justify-the-means worldview. Having said that, it depicts liberals, from President David Palmer (the only character explicitly identified as a Democrat) to Senator Blaine Mayer, as reasonable and sympathetic characters who (usually) don't stray into Strawman Political or Author Tract territory.
Tony Almeida is frequently seen drinking out of a Chicago Cubs mug because the actor, Carlos Bernard, is a huge fan of the team.
Development Gag: The wedding side story in season 2 was a nod to the original concept that 24 be a comedy about preparing for a wedding.
Development Hell: A feature film adaptation of the series has been in the works for years.
Executive Meddling: The reason Keeler survives the crash and subsequently disappears was thanks to a network mandate that the writers couldn't kill off a sitting President, as was originally intended in the Air Force One attack.
Front 13 Back 11: Bauer's wife and daughter were rescued in the 13th Hour of Day 1 as a precaution against the series being Cut Short. The final scene in that episode where a second assassin was dispatched to kill Senator Palmer could have been cut cleanly.
Fan Nickname: In season 8, Jack himself was given the nickname, "DarthBauer◊". Interestingly, when one would call him this nickname, he can be considered as the Darth Vader to Kim's Princess Leia.
I Want You to Meet an Old Friend of Mine: Victor Drazen has a personal vendetta against Jack Bauer. His actor Dennis Hopper coincidentally starred with Kiefer Sutherland in a 1990 comedy-drama called Flashback. Jack's old friend Carl Benton was played by Robert Carlyle, and the two previously starred in a war film entitled To End All Wars, which happened to come out just a few months before 24 premiered.
Shrug of God: The writers have not settled on what the ultimate fate of Wayne Palmer was after the events of Day 6. A newspaper prop in 24: Redemption viewable by freezing the movie indicates he died sometime between the sixth season and the movie, but the writers have stated that for all they know, he might still be alive.
Trope Namer: 24 has named the following tropes on this wiki:
Jack Bauer Interrogation Technique: The use of force or downright torture during interrogation. No less than 67 scenes involving interrogation were counted in the first five seasons, many of them involving the inflicting of physical pain, and mostly involving Jack Bauer.
"You probably don't think that I can force this towel down your throat. But trust me, I can. All the way. Except I'd hold onto this one little bit at the end. When your stomach starts to digest it, I pull it out. Taking your stomach lining with it. For most people it would take about a week to die. It's very painful."
Trapped by Mountain Lions: invokedA subplot with no relation to the main storyline that is often used as Filler to give one or more characters something to do on-screen. Named for a subplot in season 2 where Kim Bauer is trapped in the wilderness by a mountain lion, an event that is often held to be irrelevant to the rest of the story.
Real-Life Relative: The actors who played George Mason and Nina Myers married between the first and second season, making the interrogation between them in the latter rather interesting to watch.
Season 6's Darren McCarthy was initially cast as Eddie Izzard, but he was forced to cancel due to scheduling reasons.
The series was originally conceived as a comedy about preparing for a wedding.
The actor who played Kevin Carroll (the false Alan York in the first season), Richard Burgi, was originally cast in the role of Jack Bauer. He would have had that role if they hadn't been able to get Kiefer. Once Sutherland was brought on board, Burgi accepted the role of Carroll.
At one point, Joel Surnow wanted to acquire the rights to The Da Vinci Code in hopes of working it into a plotline for the show's third season, but Dan Brown rejected him. How he would have worked Jack Bauer into a story about Leonardo da Vinci, Pagan cults and Jesus' family is anyone's guess.