The TV show aired after the Super Bowl, especially if it's a drama, will do this for the audience that can be many times greater than any previously aired episode.
Game Shows: Pilot episodes will often have the host use the "As You Know" phrase (or similar wording), to explain the rules. This is to give potential TV station executives a sense that this was actually not the first episode but an ongoing series.
24: Nearly every episode starts with CTU in a room having a meeting in which they recap the last episode. Lampshaded with Chloe O'Brien, who As You Knows constantly and tactlessly, to the great annoyance of her co-workers.
This tendency was parodied in this fourth wall-breaking parody on the Australian sketch comedy show The Big Bite.
Spoofed on the series 'Allo 'Allo!, in this case, as with the show in general, it was meant to mock the format of wartime dramas of the day. However, as the show was later aired on other networks with episodes out of order, the utterly tongue-in-cheek recaps became somewhat necessary. Even the characters themselves occasionally got confused by what was going on after it was explained to them by another character. The constant shell game with the real and forged copies of the Fallen Madonna (with the Big Boobies) was a particular offender at this.
America Unearthed: uses this frequently when Scott is interviewing an expert and at other points.
Used straightly, if a little awkwardly, in "City of...". Since Angel is a spinoff of Buffy, new viewers would not be aware of Angel's intricate backstory. It was worked in by a new character, Doyle, showing off how much he knew about Angel by reciting Angel's life story. It was also played with at the start of the episode, when Angel starts pouring out his life story to a man in a bar, as he's pretending to be drunk while stalking some vampires. Angel lampshades the first one by pointing out to Doyle that yeah, he knows, he was there.
And in "Damage", Andrew from Buffy makes a guest appearance to deliver a load of exposition for non-Buffy viewers on what a Vampire Slayer is, and how an insane Slayer ended up in Los Angeles.
Angel: That's, um... really great, but we... actually know all that.
The Netflix season of Arrested Development just loves doing this, and then lampshading it, repeatedly. One scene in episode 11 consists almost entirely of Sally Sitwell and Tony Wonder expositing their plans to each other, while saying things like, "As long as we're recapping things we both already know..."
In Auction Kings, the experts will often tell Paul/Jon/Cindy things they would know for the benefit of likely less educated home viewers.
Babylon 5 tended to use this frequently throughout the series ("Supplies have been hard to come by since we declared independence from Earth.") due to a lack of Previously On segments. In Babylon-Squared there was literally "As you know, Garibaldi, all Earth Force ships are equipped with a transponder..."
Perhaps the example with the clumsiest dialogue is in Messages From Earth, when G'Kar tells Garibaldi "[I have] two weeks down, six to go before I've repaid my debt to society for attacking Mollari". He's explaining this to Babylon 5's head of security. Who was sat next to him in court as he was sentenced just two episodes prior.
JMS does at least admit in the DVD commentaries that yes, these lines have to be there because people might not watch every week, and yes, it's very clunky and not naturalistic dialogue at all, and he knows that, and he knows that we know that, but it's a TV show and that's one of the limitations of the medium.
At the beginning of the pilot episode, the theoretical physicist with two Ph.D.s and an IQ of 187 is explaining the Double Slit Experiment to the experimental physicist with a Ph.D and an IQ of 173. But it was for a T-Shirt!
On occasion, Sheldon explains science-related things to Howard on the assumption that he won't know them (being an engineer, he's not what Sheldon thinks of as a real scientist). This enables him to inform the audience, for example, who Richard Feynman was, without implying the exposition isn't considered weird in-universe (as Howard always objects to being patronised in this way).
The Blacklist: In "The Kingmaker", Elizabeth Keane tells the titular villain his own MO. This was after he'd already (justifiably) spelt it out to his latest victim, by which point it was already obvious.
In one last-season episode of Boston Legal, there's a casual mention of "Finlay-Crevette, a law firm you know well". Justified in that Paul's talking to Denny, who has Alzheimer's and may well have forgotten.
Inverted in the Buffy the Vampire Slayer episode "Lies My Parents Told Me", when Robin needs to be brought up to speed on what has happened to Spike in the last few years, without annoying the regular viewers to whom it's not news. Buffy's condensed exposition hits all the keywords but leaves Robin still in the dark.
Parodied in the Castle episode "Swan Song", where the title character is followed by documentary film producers. Castle prompts Beckett to "As You Know" to explain who Lanie is, for the benefit of the audience.
Poorly done in Chopped Championship. Each round featured chefs who had won an episode in the past. So host Ted Allen starts off with "I'm sure you remember the rules..." before going right into his standard rules script.
Criminal Minds has a unique twist to this trope. Each episode typically starts with the case being presented to the team (originally by JJ, then Garcia took over a few seasons later, and others sometimes take turns), which would seem to avert the trope, as it's one person telling the others what they don't know. Except, in an effort to break up the Info Dump, they like to spread the dialogue around. So everyone flips open their file (or checks their tablet), and they take turns announcing the information to the table. Even when someone needs clarification on a point, it's not necessarily the presenter who provides that clarification.
The Crown: People often explain things to Elizabeth about royalty that she would almost certainly already know. In one scene, she's reminded that her father, King George VI, who is known as "Bertie" in the family, changed his name from Albert when he became king.
The CSI detectives are always explaining rudimentary forensics to one another.
Lampshaded in the season 10 episode "Working Stiffs". Hodges explains what a machine (D.I.V.A) does while Langston is using it; after Hodges finishes, Langston says, "I know how it works — I'm doing it." Hodges retorts, "Yes, but it was a lucid and an entertaining explanation of the process."
This is particularly bad on the spinoffs, where characters have a tendency to explain a scientific concept to each other right after the other character suggests it.
Occasionally justified, if the character doing the explaining is implied to be practicing the As You Know for later presentation in court. A jury is bound to need this kind of information, so reviewing how a test works to whomever is at hand could be viewed as practice for testifying about the results in layman's terms.
Also justified in the CSI: Miami episode where Tim Speedle got killed; it is determined that he was left momentarily defenseless when his gun jammed; then Caleigh and H begin bantering back and forth that Speed's previously established bad gun maintenance habits might be to blame, but that conclusion would require speculation and "we don't speculate." They're not telling each other stuff they already know; rather, they're rationalizing their decision not to sully Speed's name by implicating him in his own death.
"The Space Museum": The second episode is notorious for this. After a really scary and surreal first episode in which the characters wander around an invisible museum and witness their own corpses, the second episode kicks off with an overweight, middle-aged Rubber Forehead Alien delivering a ton of Call a Rabbit a "Smeerp"Technobabble beginning with "As you know..." This is a rare example of the speech managing to be unnecessary to the other character and incomprehensible to the audience at the same time. Helpfully pointed out by Robert Shearman on a DVD special feature, in which he ponders whether the sequence is "badly written" or "amazingly badly written".
The show ran into this problem when Romana (another Time Lord who actually was cleverer than the Doctor) travelled with the Doctor. In this case, however, the sheer quality of the two actresses who played Romana meant that few really noticed plus Romana was meant to be a bit naïve. Ironically, part of the original intention of the companion was to have an Audience Surrogate, so it would be less "As You Know" than "Did You Know?"
A particularly bizarre Doctor Who example occurs in the final episode of "The Armageddon Factor", where two incidental characters As You Know a recap of the Doctor's current predicament for the audience's benefit although the Doctor is across the star system and out of contact, and hasn't been for some time, so there's no way they could know the events they relate.
Another extremely blatant example is in the serial "Resurrection of the Daleks", when the character rescuing Davros from cryonic suspension explains the plot of "Destiny of the Daleks" to him. This doesn't even start As You Know; Davros reacts as if the events that led to his being placed in cryonic suspension are entirely new to him.
Isaac: We wait here until the Doctor comes to pick us up in your ship. Rory: Yes. I know. I was there when we agreed it. Isaac: Yeah, I said that more for my benefit than yours.
Dollhouse has a scene with Dewitt explaining how a rich psycho got out of a bunch of crimes, followed by Boyd saying "And by that, do you mean..." and she responds with what she was actually hinting at. After he does it twice she hangs a lampshade on it with "There is no need to continue to translate me."
Downton Abbey: It is all too common for characters to give massive info dumps for things they should know about but the audience doesn't. This includes inheritance laws, how to run the downstairs, and how Christmas is at Downton. Also very common for characters to reference events that happened in pass seasons, asking if another character remembers them. This is lampshaded by Robert, who snarkily replies when asked if he remembers Mr. Pamuk that he remembers the man that DIED at Downton.
Dr. Quinn, Medicine Woman: Colleen, trying to stop Jake from shooting Sully: "He saved your life! Those Indians wanted to kill you after you accidentally shot one of them, and he persuaded them not to! You owe him your life."
Finding Your Roots: Whenever trying to discover the ancestors of black guests, or any guest with African DNA, Henry Louis Gates Jr. makes a point of reminding the viewers that slavery is the big barrier to finding the ancestors of said guests.
Mocked in the episode "Roz and the Schnozz". After Daphne has spent a full minute going on about how generous Frasier was to buy her a pair of sapphire earings:
Frasier: Dear God, she believes they're genuine sapphires. Martin: (sarcastic) Gee, ya think?
The episode "Coots and Ladders", has a Framing Story of Frasier describing his day to Niles, and Niles impatiently waiting for him to get to the point. When he gets to a scene Niles was actually present for, Niles interrupts "Yes, and then we all looked at the pictures, I remember it as if it were four hours ago!"
Played for Laughs in The Fresh Prince of Bel-Air where Will states that he got into an argument with a new boyfriend of a girl he likes, and states that the fight will be easy based on how the person sounded. When the person walks in, Will freezes with an Oh, Crap! face as he recognizes him. This works brilliantly for people who watch the show later or just didn't know exactly who he was at the time. Geoffrey turns this into a Crowning Moment of Funny, having heard Will's remarks about easily beating him in a fight.
Geoffrey: Introducing Mister Evander Holyfield. (beat) Undisputed Heavyweight Boxing Champion of the World!
Friends usually subverts this by explaining things to a cast member who wasn't there at the time or forgets. For instance, when Joey doesn't remember about Chandler's former roommate, prompting Rachel to explain him (and thus, the audience) how her situation paralleled his. That one worked. Unlike the time Ross (uncharacteristically) forgot about Mark (a chief reason for his relationship with Rachel going to the crapper) and Rachel had to remind him about who he was. In fairness, no-one had mentioned Mark for at least five years, and Ross did know who he was once Rachel had jogged his memory.
Fringe gets away with this pretty well by giving all the As You Know lines to Cloudcuckoolander Walter Bishop. After a few months, everyone else just accepts it and stops trying to remind him that they already know this stuff. Walter has brain damage and spent many years in a mental institution. As a result he forgot a lot of important things he did and is extremely scatterbrained. His use of these speeches is portrayed as reminding himself that he knows this stuff.
Get Smart. Averted in "The Impossible Mission" when Max gets a taped briefing from the Chief.
Chief: We know the Leader plans to get the theory out of the country tonight. Should he succeed in delivering Dr Helman's theory to KAOS headquarters in Europe, the human race will face extinction through Helmanitus. Max: What is that?! Chief:I don't have to tell you what that is.
Gilligan's Island: Shows up in the TV reunion movie, "Rescue From Gilligan's Island". Gilligan finds a piece of equipment that fell into the lagoon from a satellite. The Professor uses it to repair his barometer, which detects an upcoming storm the island probably won't survive. When the others press for details, the Professor begins:
Professor: As you are aware, the radio and all the rest of my instruments haven't worked for over ten years.
House almost always explains to either his team or to Wilson or to the patients just how they were dying. It's perhaps justified by House having an obsession with this, and in one episode, he gets in a bad mood when a dying patient doesn't want to hear what she's dying of. This gives him the epiphany he needed to solve the case and cure her.
Mocked in an episode where House stops a surgery by spitting all over the sterile equipment; in case the dimmer members of the audience didn't get the significance, Nurse Exposition points out "There's no way we can do the surgery now!" The exasperated surgeon gives her a withering look and yells "YA THINK?!?"
And then for some more metaphors. But these are lampshaded quite often.
How I Met Your Mother usually averts this by having future Ted provide an explanation for his kids, but sometimes it's played straight, often lampshaded. However, Ted constantly explaining things to the kids gets a little weird in that the kids are supposed to be hearing this whole story in one sitting (they don't age or change clothes for nine seasons) but the audience is likely to forget details because they are hearing it over nine years. For example, in the late season 5 episode "The Wedding Bride," Ted explains that he had been engaged to Stella but she left him at the altar to get back together with her ex, Tony. This is necessary because the plot of the episode is about a movie written by Tony that clearly is mocking Ted, and the audience hasn't seen Stella or Tony since the end of season 4, and then only briefly. But the kids would have heard the story about Ted's engagement to Stella anywhere between fifteen minutes to a few hours ago (depending on how long it's actually taking Ted to tell the story), so recapping this would seem incredibly odd from their point of view.
Done a fair amount by Winston in Human Target, although tends to be of the form "Now, remember..." or "Here's the plan..." although it's something the putative listener wouldn't forget or already knows.
The pilot of Intelligence is full of this. One exposition starts with the phrase "as most of you know".
On Law & Order (and presumably other Law Procedural media), lawyers summarize court opinions to each other. Sometimes a lawyer or judge will explain an opinion to the person who cited it.
Somewhat justified — lawyers have to be able to distinguish the case's meaning from the facts, and then apply it to their particular situation. And they have to be able to challenge arguments that the case they just cited shouldn't apply. And in the case of the judges, it's often done as a method of interpreting the law based on the arguments of the lawyers (and playing Devil's Advocate in the process by challenging their interpretation), which is partly what judges are supposed to do.
Also, judges very often don't read the briefs. Lawyers humor them and summarize the arguments.
Lampshaded in Life on Mars during an interrogation. Except indeed, he was: he was in fact speaking for the benefit of a concealed microphone.
Sam: Guv, you have just used unnecessary restraint on a suspect by handcuffing him to a chair. Gene: (disgustedly) What are you, the narrator?
In episode 2 of Luck, Ace has a rather awkward monologue explaining why he was in prison. They actually try to sell us on the idea that the person he's talking to (his bodyguard and best friend) wouldn't already know this, but it's very hard to believe.
In The L Word this duty often falls to the gossipy character Alice, who, coincidentally, is a blogger, journalist, and TV personality. She knows everyone else in the show, they tell her what is happening and she occasionally recaps everyone else's life.
Madam Secretary will often do this with political issues by having Liz's staffers talk about it during meetings.
Illya: To our mission! May we successfully proceed to the vault beneath the gambling casino, where THRUSH keeps its entire treasure for Western Hemisphere operations. Napoleon: While we decimate THRUSH's ability to carry out their operations by destroying the 55 million dollars in their vault.
This shows up in a skit, complete with blatant fourth-wall breaking:
Psychiatrist: Er, nurse! Receptionist: Yes? Psychiatrist: (whispering) Er, you don't think you should make it clear that I'm a psychiatrist? Receptionist: What? Psychiatrist: Well, I could be any type of doctor. Receptionist: Well I can't come in and say "Psychiatrist Larch" or "Dr Larch who is a psychiatrist". Oh, anyway, look, it's written on the door. Psychiatrist: (still whispering) That's outside. Receptionist: Well, I don't care, you'll just have to do it yourself. Psychiatrist: (goes "brr brr", then picks up phone) Hello. Er, no, wrong number I'm afraid, this is a psychiatrist speaking.
Also Lampshaded in the sketch about painting the Last Supper where the bishop introducing Michelangelo to the Pope launches into a recitation of Michelangelo's history before being cut off by the Pope.
At the end of The Morning Show Episode 6, Alex's daughter goes into exposition while describing her father's (Alex's husband's) accomplishments.
This might be the reason why the characters in My So-Called Life were almost always referred to by full name. Although it does happen in high schools, considering your social circle can technically extend to include all of the students at your school, and all of the students that have graduated in the last two years. There are a lot of Jordans at a school of 5,000.
The Orville: In "New Dimensions", Kelly explains to LaMarr that with the advent of matter replicators, status and rank in society was no longer measured by wealth and physical possessions but rather skill and reputation. While this is something LaMarr already knows, she does this recap to set up her pitch that he consider pursuing the Chief Engineering position.
The Outer Limits (1995): The opening of season 1's "The New Breed" provides an infodump on nanotechnology that also contains several basic biological principles that the audience in the room (all scientists) should already be perfectly aware of.
Since most of the episodes takes place in self contained universes (mostly) this happens a lot to clue the viewer into the backstory.
On Oz, they did this frequently as they went from one storyline to another. It's especially obvious when watching episodes in quick succession.
The Partridge Family: When the kids complain about the crappy bed and breakfast where they just spent the night, Shirley says, "I tried to make it home last night, but we were all too tired. This was the only place around."
Urko: Where's Mema? What's keeping him? Zako: Urko, I'm sure he'll be back as soon as he has searched the city. It would be a good place for the fugitives to hide. Urko: When I ask you a question, don't tell me something I already know!
Played with in Porridge, in the episode "Pardon Me", with Barrowclough informing the prison governor of a way they can get out of a huge media event over one of the prisoners' proposed hunger strike. Instead, they can simply pardon said prisoner (his goal). Barrowclough prefaces every statement about the Penal Code with "As I'm sure you know...", but only out of politeness; it's patently obvious that the prison governor does not know:
Barrowclough: There may be a way out of this, you see, a solution to our problem. As I'm sure you're... well aware, given your deep knowledge of the Penal Code. Governor: Yeeeeesss ... Refresh my memory, would you, Mr Barrowclough, please? Barrowclough: Well, you see, it's Subsection 23, Part 3, Paragraph D. Governor: Yes, D, of course, D... Jog my memory again, would you, Mr Barrowclough? Barrowclough: Well, as I'm sure you... know, sir...
Ron: Now, everyone knows that the leading cause of deaths in a corporate environment is Superman crashing through the building during a big fight. That's just a fact. [everyone nods]
Lampshaded in Psych, like virtually every other trope in existence. Juliet explains to Shawn and Gus that Lassiter is holding off The Chief for 24 hours so they can find Shawn's dad and Juliet's stepfather prompting this exchange:
Gus: You already told us that in the car, Jules. Juliet: (mockingly) Well, I need to cover my bases, Gus. Shawn: (confused) For who?
Done especially badly in the TV movie Rose Red, when Sister notices that the roses in the greenhouse are blooming and gasps in disbelief, "They're coming to life again!". Presumably Easy Amnesia is to blame, as she's the one who'd pointed out this very phenomenon to the same character in the previous episode, and hadn't even been surprised about it then (because her psychic little sister makes such things happen all the time). This is particularly jarring when the miniseries is played in its entirety on the same day, as these two scenes are shown less than an hour apart.
Jerry: I mean, the whole thing is ironic. Think of it: Here the guy is nice enough to give you a box of very fine Cuban cigars... George: Yeah, I know what happened. Jerry: No, but wait, wait: And then you dump them off onto Kramer... George: I know. Jerry: ...Who proceeds to burn the man's cabin down with one of those very same cigars! It's very comical.
Jack: It goes without saying... Cassie: Then why say it? Jack: What? Cassie: Whatever it was you were about to say. Jack: Because it needs to be said. DD: Not if it goes without saying. Jack: But it's very important information. Shane: It's already been said. Jack: Yes. DD: To us? Jack: Of course. Cassie: So you're just saying it for the benefit of someone who might be watching who didn't hear you say it before? Jack: (pause) I guess I am. Jack: (on other phone) Dr. Frankel, it's happening again. The unshakeable feeling I'm a sidekick whose only purpose is to give exposition in an action-adventure show.
And in episode 20:
Cassie: What a day, huh?! Parachuting into a cemetery because the (?) was being guarded and it was the only way in, and exposing a deadly double agent who was trying to elude capture by faking his own death and being buried with an oxygen tank only to be dug up later. DD: We knew all that, you know. Cassie: Oh, I know. I was just saying that for anyone who might have been wondering why we were going through all the trouble. Shane: Who would be wondering? Cassie: I don't know, anyone. Cassie: Look, I never told you guys this. It's kind of embarrassing. But sometimes I get the weirdest feeling that people are watching us. Like they're listening in on every single thing we do or say. Shane: Hey, I get that feeling too. DD: So do I. (they all look at the camera)
Chloe stops Clark from leaving so that she can remind him of the very reason that he's leaving, which both he and the audience are well aware of, just so that she can spill a secret to one of Lex's henchmen, secretly listening. This isn't surprising as Chloe is saddled with about 90% of the show's exposition in every episode anyway, so it was only a matter of time before she got sloppy.
She does it again, even worse, with the guy who can become invisible. When they have figured out he's evil and Clark needs to stop him and all, Chloe thinks he might have figured Clark's Achilles' Heel since he can become invisible, so she asks him and he is there and finds out. Quite infuriating because she asked "Are you sure he doesn't know you feel bad around meteor rocks?" instead of the safer "Are you sure he doesn't know your weakness?". Doubly infuriating because for about two seasons she had already been calling them "Kryptonite", and only went back to "meteor rocks" for that one scene.
Used rather blatantly in Sons of Anarchy when Clay returns a bloody knife to the man he's been blackmailing, which factored into events of the previous season. Clay then explains that it's a murder weapon with the man's fingerprints on it, like you could forget something like that. The man snaps that he knows what it is.
This happens all the time in the later seasons of Stargate SG-1 as there's more and more backstory to be filled in as it becomes plot-relevant. Similarly, since Stargate Atlantis often runs into situations very similar to ones that have already happened in the Milky Way, there's a lot of exposition required to explain how the previous situation relates to the current one, which most characters would already know.
An episode of Stargate Atlantis uses it so blatantly (starting by emphasising the phrase "as you know") it seems rather like a soliloquy. The fourth wall goes back up as soon as the infodump's finished. Another example is actually justified in universe, Sheppard mentions his recent promotion to Lieutenant Colonel a month after it supposedly happened. It turns out he has been slipping it into every conversation he could that whole time.
Starsky & Hutch does this quite a lot. For example, between two villains in "Silence":
Kim: You just tell Bessinger to keep his mouth shut and lay low. No more robberies until the heat lets up. Father Ignatius: Kim, you're forgetting. My order is sending three more priests from back east next week to help out with the work here. If we're not gone like we plan to be, they'll know I'm not the real Ignatius.
Spock: As we know, the value of pi is a transcendental figure without resolution. The computer banks will work on this problem to the exclusion of all else until we order it to stop.
In "Assignment: Earth", the Beta 5 computer insists that Gary Seven describe his assignment. Justified in that Seven is a new arrival and the computer is confirming his identity before obeying his orders or giving him information.
In the episode "The Pegasus", Admiral Erik Pressman briefs Captain Picard and Commander Riker on the loss of his former ship, the USS Pegasus. He chooses to open his briefing with the words "as you know..." and then proceeds to tell Picard and Riker what they already know. Picard chimes in with an "I remember reading about that," and continues to tell the story of the Pegasus for the benefit of no one else in the scene.
Averted (badly) in "The Bonding", which starts out without the Captian's log info dump, and instead we find out what's going on through Captain Picard listening to his bridge officers telling him all they know about the planet they're investigating. Picard reacts like this is the first time he heard this information. This only happens, however, when an away team led by Worf has been down on the planet for quite a while. As SF Debris pointed out in his review of the episode, it makes Picard look totally clueless since he brought his ship to this planet and sent down an away team without having any idea as to what they're doing or why.
Subverted in the episode "Code of Honour", where Picard starts to describe events in Earth history, before lampshading that as the captain he's "entitled to ramble on about something everyone knows." Played straight earlier in the same episode, where Picard is apparently only being told their mission and who he's meeting with as he's on the turbolift to greet them.
This happens every time Q makes an appearance in the first couple of seasons (other than, obviously, the pilot). Characters take turns berating Q for the nasty things he's done to the Enterprise crew, recounting them in order. They all but say, "And in your next guest appearance ..." Particularly egregious in that they're not just telling a character what he obviously already knows, they're telling an omniscient character what he couldn't possibly have forgotten.
Lampshaded in "All Good Things" which features Picard spontaneously jumping through different points in time, while keeping his memories of each point in time. Somewhat justified as it's established that he has a disease in the episode that affects his memory, and he's also disoriented by the time jumping causing him to occasionally get things wrong.
La Forge: There is no Neutral Zone. Remember? Picard: Right. Right. Klingons. In this time period, the Klingons have taken over the Romulan Empire. La Forge: And right now, relations between us and the Klingons aren't too cozy. Picard I know that! I haven't completely lost my mind, you know!
Occurs in "Trials and Tribble-ations" when Chief O'Brien and Bashir are searching Kirk's Enterprise for a Klingon criminal.
Bashir: I'm going to widen the scan radius. If I can figure out how. O'Brien: Keep the scan field below twenty milliwatts, otherwise you'll set off the internal sensors. Bashir: Thank you, Chief. I was listening during the mission briefing.
Slightly better done in the episode "In The Pale Moonlight", when Garak and Sisko are discussing a Romulan Senator who they need to convince to support their side of the Dominion War.
Garak: His name is Vreenak. He's been a key member of the Romulan Senate for the past fourteen years. He's Secretary of the War Plans Council, Vice Chairman of the Tal Shiar, and one of the most trusted advisors to Proconsul Neral. Sisko: He's also the man that negotiated the non-aggression pact with the Dominion. Garak: Since you're familiar with him, I'll skip the rest of his biography.
Star Trek: Picard: In "Et in Arcadia Ego, Part 2", Narissa reminds her brother that "Our parents died for this, Narek. Many more gave their lives."
Sunset Beach in absolute spades. "Since you were almost killed by that tidal wave you've been... preoccupied, to say the least."
A very awkward exposition scene in the pilot consists of Sam describing his life story to Dean, who grew up with him so already knows all of this. Eric Kripke has admitted that he regrets writing this scene, and that when he watches it he just wants Dean to interrupt and say "I know! I was there!"
Especially in the first series, the brothers have very hammy conversations about hunting methods which should be utterly basic to them — two people who have been monster hunting all their lives. For example, every single mention of salt comes with an explanation that it slows down spirits, regardless of how many times it's been in an episode before.
An annoying one from the second episode of Kyōryū Sentai Zyuranger had the team telling the story of how they were put in stasis by their tribes in case of Bandora's return. It's abundantly clear that everyone in the room knows the story.
The first episode of its counterpart Mighty Morphin' Power Rangers used the "introduction by name" version; the five Rangers-to-be are all mentioned by name in the first fifteen seconds.
Tinker, Tailor, Soldier, Spy had a good justification. George Smiley puts out a couple of milkbottles on the steps of a safehouse, then goes inside and confirms that this is, in fact, the correct "It's safe to come in" signal.
Peter: Yes George, for the second time. Smiley: Is it? Well let's not pretend we're not nervous.
Near the end of the first season of True Blood, Bill Compton is forced to turn Jessica Hamby. He is asked if he knows how to do it, and responds that, though he has never done it personally, he knows how to do it. The next few scenes consist of vampires explaining how it works, with Bill repeatedly telling them that he knows how it works.
Used in the season 2 finale of Veronica Mars, in which the Big Bad and Veronica take a 5 minute timeout before he tries to kill her, for them to confirm yes, she knows everything.
Lampshaded in Watchmen; the overeager New Meat FBI agent calls his supervisor after making a big discovery and begins the call with "Do you remember when you told me..." and proceeds to remind her of his entire assignment including the rationale for pursuing it. She wearily replies,
Det. Blake: Yes, Petey. I remember it as if I said all of that to you verbatim.
In order for viewers of The West Wing to know the significance of any of the laws/political issues/etc. the characters were talking about, someone (usually Donna, who was both politically inexperienced and very inquisitive) would ask someone else to explain the issue, in the vein of interns on ER. Although the writers of The West Wing usually described this trope as a necessary evil, they occasionally could get pretty creative with it, such as leaving the audience intentionally in the dark for a good chunk of the episode, only showing the characters' reactions to the mysterious problem, which resulted in the audience either waiting for the point to be revealed or trying to puzzle out Noodle Implements, making for a more suspenseful episode and lots of Genius Bonuses. Or they sometimes would forego the explain-to-the-non-expert version in favor of a character being out of the loop for various reasons and humorously trying to bluff knowledge, or having someone (usually Toby) rant about the issue at length, providing exposition but not just exposition.
The White Queen: Queen Anne reminds King Richard III of an important fact that he's well-aware of.
Anne: Take care you do not cut the Neville affinity away from yourself. I am the Kingmaker's Daughter, and many in the North only follow you for love of me. They'll turn against you if they think you shame me. Richard: I know that.
The Wire generally averts this as a rule in a show that aims to be clever with its exposition and relies on Let Me Get This Straight... when new information is required. There's a rare but very neat straight example during D'Angelo Barksdale's funeral, when Proposition Joe approaches Stringer Bell to talk shop and prefaces one of his propositions with a summation of the Barksdale dilemma: prime real estate but weak product. Stringer interrupts Joe and asks "when are you gonna tell me something I don't know?", urging Joe to get to the point.
In Wonder Woman (1975) whenever Diana snagged a villain with her magic lasso, she would inform them "Now you have to tell the truth," something they would find out for themselves as soon as she started asking questions.
Mulder would often explain the definition of various medical conditions to Scully. Actually, he was explaining it to the audience, but that didn't make it any less silly considering that Scully was a medical doctor and Mulder wasn't.
And vice versa: Scully often explained pretty basic terminology to Mulder including definitions from his specialist field, criminal psychology. In one particularly good example, Mulder doesn't know what Munchausen-by-Proxy is, and Scully has to explain it. Yet about two scenes later, when she uses the term to a complete layman (the father in question) he immediately understands the implication.
Played with in Yes, Minister. Not having read the papers, Jim Hacker often seems to know as much as the audience, but tries to hide it from his officials. In "A Victory For Democracy", notably, neither Hacker nor Sir Humphrey nor Bernard nor, indeed, the Foreign Secretary seem to precisely know what is happening on St. George's Island (or even where it is). The trope's name is invoked during a conversation between Humphrey and the Permanent Secretary for Foreign Affairs (the one person who knows anything about it), with Humphrey mainly making educated guesses and agreeing with whatever is said. The Foreign Secretary, despite clearly picking up on Humphrey's ignorance, humours him because Sir Humphrey is very on the ball in most cases, and there really has been no reason for Humphrey to know about the globally irrelevant island until now.
Yes, Prime Minister: Subverted. Whenever one character says to another "As you know", it means that the second character does not know and needs to be told, and the first character is intentionally allowing the second character to "save face".
In the second episode of Young Blades, D'Artagnan recaps the events of the first episode by telling Jacqueline, in the tone of a lecture, "But we must never forget, even for a moment, that you are a fugitive, wanted for murder." Most of the other episodes have a short dialogue where Jacqueline and D'Artagnan remind each other that Jacqueline is a woman disguised as a man, in case the audience didn't notice.