Paul McCrane's characters tend to die painful onscreen deaths. Guess what happens to Graem Bauer?
Trip's wife is carrying twins, and they're kicking. She's lucky it's not triplets.
The final two episodes of Season 8 are pretty much one giant one for Kiefer Sutherland's role in Phone Booth. Much like the Caller, Jack is smugly trailing a sniper rifle over a character while giving him directions over the phone.
The first episode of Season 9 isn't the first time this year Kiefer Sutherland has had to infiltrate a CIA black site to rescue a female former ally from imprisonment and torture, as anyone who's played Metal Gear Solid V: Ground Zeroes will know.
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.
Though it does become an issue in Live Another Day, as it seems like a large part of why the show was brought back was to make a No Celebrities Were Harmed strawman of Julian Assange who actively helps terrorists.
The number of former Star Trek (particularly Enterprise) actors who appeared on the show dramatically increased since Brannon Braga and Manny Coto joined on as executive producers. Peter Weller in particular has appeared in four Coto-produced shows (Odyssey 5, Enterprise, 24, and Dexter).
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.
British Julian Sands as Russian separatist Vladimir Bierko.
German Jürgen Prochnow as Russian Sergei Bazhaev.
Northern Irish Michelle Fairley as English Margot Al-Harazi.
And a short list of Middle Eastern examples:
Syed Ali was played by Mexican/Italian-descended Francesco Quinn.
Navi Araz was played by Hispanic Nestor Serrano.
Habib Marwan was played by Afrikaner Arnold Vosloo.
Abu Fayed was played by Greek-descended Adoni Maropis.
Omar Hassan was played by Indian Anil Kapoor.
Nadia Yassir was played by Mexican/Romanian Marisol Nichols.
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.
Curtis Manning was called "Black Bauer" or "Black-Jack" for effectively being just as badass as Jack, and for being... well, black.
Fans of Larry Moss in Season 7 affectionately referred to him as "Boss Moss".
The bag of equipment Jack can sometimes be seen toting was known as his "Jack-pack."
Television Without Pity had a cottage industry of these for 24, at least in the first few seasons worth of recaps. Some of the more notable ones include "Bitchelle" for Michelle Dessler, "Soul Patch" for Tony Almeida, "Spawn of Kiefer" for Kim Bauer, and "Im-ho-Terror" for Marwan...
"Sparky" for Paul Raines, after Jack used electricity to torture him. There's also the far-from-creative "Agent Hobbit" for the season five character played by Sean Astin...
Fast Karate For The Gentleman makes a habit of creating dozens of these, for pretty much every character not in the core cast. Special mention goes to Special Agent Babykins, Chloe's son Jib Jub, and the President of Not-Iran.
And for season 6 Lord Denethor was working in the Russian government as an inside man for the terrorists, showing that he can be a bastard even without Sauron's corruption. Or maybe it was Walternate all along.
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.
Keep Circulating the Tapes: Although the entire series is on DVD and can be streamed on Amazon, the "Previously on 24" recaps that originally appeared in the original airings of the first season have not been used again and have not been featured in any reruns, home video releases, or streaming services. It's extremely odd since the recaps from all other seasons are featured in reruns and home releases.
Disclosed memos from within the former Bush administration suggest that, if 24's torture methods didn't inspire the initial events at Abu Ghraib Prison and Guatanamo Bay Prison Camp, they at least inspired their justification and continuation to this day.
On a less controversial note, the suspects of the Abu Ghraib abuses claimed 24 as inspiration for their tactics, and military intelligence instructors have complained to reporters that they have to drill 24 and its depiction of torture out of the heads of new students.
The Other Marty: Margo, the antagonist of "Live Another Day," which was originally supposed to be played by actress Judy Davis. As principal photography began though, Davis was forced to drop out because of family concerns, so the role was recast to Michelle Fairley.
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. As of April 2014, he's labeled as "Deceased" on the 24 wiki.
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. This would soon afterward see the light of day as Big Day, though the show quickly crashed and burned.
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.
When a movie was still in the works, Tony Scott was considered to direct it. His suicide was one of the factors that ended the project.