Most shows use the "ticking clock" as a metaphor. 24 Takes that metaphor and has a drunken night out with it.
While the name of the show is 24, the unoffical subtitle is The Jack Bauer Power Hour.
Like many actions shows the audience must suspend their disbelief and just enjoy the show without thinking too hard about certain things like how people can get across LA in 4 minutes while everyone else spends 3 hours in traffic just to cross the street.(On Cracked: 4 Things 24 Would Like You To Believe)
Jack Bauer is one step removed from being a superhero. A former member of the LAPD SWAT force, Delta Force, the CIA, and finally CTU, Jack has been trained in 100 different methods to kill a human being. He also has a super-healing ability that has allowed Jack to survive having his heart stop(Season 2), overcome Heroin addiction in one day(Season 3), and take 2 years worth of torture from the Chinese government and shake it off like they only tickled him(Season 6).
Kiefer Sutherland portrays THE American hero, his loyalty never waivers for a second, even when he's asked to die on behalf of his country. The thing is, he's Canadian (On Cracked: Treason! 8 Celebrities You Won't Believe Aren't American)
Sorry about gouging your eye, eh.
Kiefer also knows how to have a really good time (On Cracked: The 11 Most Unintentionally Poignant Drunk Celebrity Videos).
Despite Keifer Sutherland's assurances that the show would still be great if they killed off Jack Bauer, the rest of the fans know that the show would be dead faster than a likeable character in mid-season.
Each season deals with Jack Bauer saving the United States of Los Angeles from imminent destruction. For 6 seasons, Los Angeles was apparently the place to be if you were a terrorist or counter-terrorist. But now, in a bold move(or a big discount in air tickets to the east coast) all the action for season 7 will take place in Washington, D.C.
CTU: To Serve and Distract you while Jack's driving to a location
The Counter Terrorist Unit (CTU) is the fictional agency that Jack Bauer works for when he isn't fired, faking his own death or quiting. CTU is filled with very capable agents that are well trained in giving Jack detailed info about every area he's about to go to while also being adept at getting into trouble that only Jack can get them out of.
They also have a mortality rate higher than people who jump out of airplanes without parachutes.
For seasons 7 only three CTU members from previous seasons will return. Chloe, the once annoying and now bearable analyst that acts like Jack's Jiminy Cricket conscience is coming back. Also Bill Buchanan, former director of CTU, will make an appearance in the season to give Jack some valuable information after which we predict he will be killed. Then SPOILER: Tony Almeida, the guy who had a literal lethal injection jabbed right into his heart and died in Jack's arms, is now back from the dead. He's also gone bad(or so we think).
While members of CTU are back, CTU itself is not, having disbanded in favor of just letting Jack save the day on his own, much like he has been doing for the past 6 seasons.
If it weren't for cell phones, 24 would not even exist. The little devices that everyone else uses for texts on what happens to them every minute(Hey, I'm sitting down now, later I'll stand up), are used by Jack and CTU agents to break into highly secure facilities and match voice prints of people talking 100 feet away (On Cracked: Jack Bauer Beta-Tests His New Cell Phone).
You might be worried that over the years 24 has been a tad repetitive. There have been several nuclear bomb scares, deadly viruses, nerve gas, even a season where the main villain was the President of the United States. So what else could there possibly be left for the writers to write about this season? Don't worry about it, just be assured that Fox uses every trick in the book to keep viewers watching (On Cracked: 5 Cheap Tricks TV Shows Use To Keep You Watching).