In "A Golden Crown," Ser Barristan Selmy's silent reaction during Lord Renly Baratheon's "The Reason You Suck" Speech to King Robert shows that he completely agrees with the younger brother.
In "Garden of Bones," Ser Loras Tyrell laughs merrily after King Renly Baratheon makes fun of Melisandre's prophecy ("Born amidst salt and smoke? Is he a ham?"), but as soon as Lady Catelyn Stark starts talking, the Knight of Flowers becomes annoyed and sighs heavily.
Loras appears to be flirting with a young nobleman in "Second Sons" while Queen Cersei recounts the story of the Rains of Castemere.
After King Joffrey gets up from his seat to inspect his new Valyrian sword, Lord Mace Tyrell raises his eyebrow at Lord Tywin Lannister, and his wordless query is, "Are you sure it's wise to give that maniac a deadly weapon?"
When the guests at the Sept of Baelor are clapping for King Joffrey and Queen Margaery, Prince Oberyn Martell turns his head slightly to the left so that he can catch a glimpse of Loras. Oberyn is bisexual, and Margaery is a gorgeous woman, yet he clearly thinks that her brother is more attractive. This doubles as a Mythology Gag, as some of the characters in the novels consider the Adonis-like Loras to be prettier than his classically beautiful sister.
Happy Endings: In "Grinches be Crazy", we get two. First, after Santa!Max has rescued Penny from being mugged, the two talk about how he's actually doing good for a change. While this is happening, the mugger is stealing another woman's purse, while Max says it'll be easy for him to find more chances to do good. The mugger and victim eventually run right past them, but Max and Penny just yell at them for being loud.
Later, while Dave and Penny are talking, Alex falls into a giant glass box for charity toys.
In Mission 21 of Tokumei Sentai Go-Busters while Gorisaki Banana and Jin Masato are having a conversation about Ryuji at a park, Beet J Stag rides a zip-line on the playground then starts running around the playground with a bug net conversing with a large piece of equipment that has a grasshopper head. He continues this while waving the bug net in the air and eventually falling on his face.
Arrested Development does this frequently, a particularly impressive one takes place after the show Mad Money moves the Bluth company up to "Risky". In the foreground Michael walks into the office talking on his phone, in the background though you can see a half fallen sign saying "risky business," a collapsed ladder, a man next to the ladder rubbing his head and a man limping dressed in his underwear, white t-shirt and sunglasses saying "I couldn't see through the glasses and I slid into the ladder" and someone else changing the number of days since accident. This all takes place in 3 seconds and is probably missed on first viewing.
During the episodes where Tobias tries to get into the Blue Man Group, blue handprints can be seen all over the walls.
In the very first scene of the very first episode of The Middleman, Wendy is talking to her mother on the phone - as a terrifying mutant breaks out of containment behind her. She stays on the phone for quite a while before it breaks through the glass wall of its pen and attacks her. It tells you something about the show.
In "The Flying Fish Zombification," the titular hero is on the phone with Ida, who is explaining to him the giant deadly flying fish is causing their current problem. And that in order to reverse the effects, the fish must be captured alive. In the background, while this discussion is going on, Wendy Watson is alternately fleeing from and fighting against said fish. She defeats it a second after the Middleman hears it must be captured alive, and looks pleased with herself for not needing his help.
Wendy also works out her anger on an interrogation droid after Ben puts their video breakup online and it becomes an internet sensation. We see the video of her going medieval on the droid's ass in the background while the Middleman is obliviously talking to Ida.
Happens in the British comedy series Teachers, the plots of which are all about the titular teachers rather than the children they teach. The latter are, however, often seen doing funny and/or bizarre things in the background. There are also animals, such as sheep and donkeys and at one point a lion in the toilets that passed without comment.
Occurs semi-frequently on My Name Is Earl; I believe they call them "bee moments" or something, based on a time Randy was trying to swat a bee in the background of a scene.
In Living Color! had a whole series of skits based on this concept. A news report takes place in the foreground of a setting (crime scene, beach, etc.) and an unnamed bystander (Jim Carrey), having noticed the camera, goofs around in the background in increasingly silly ways while the reporter and interviewee are unawares.
Also from Friends, in Season 7 Janice, Chandler's very annoying ex-girlfriend, invites herself over. As she's standing in the doorway we see Joey appear behind her. His eyes grow wide as saucers when he sees her before he silently legs it as fast as he can.
An accidental and very easy to miss variant in one episode of Hannah Montana. When the school's resident Alpha Bitch proves to be an impressive singer by belting it out in the school cafeteria, you can see an extra begin to cheer, but then stop and cover her mouth, embarrassed. That wasn't intentional, and the editors must have either missed it or thought that it didn't warrant another run-through of the scene.
In the Malcolm in the Middle episode "Traffic Jam", when Malcolm is belly-aching to Jessica about her being Canadian, Reese is shown in the background being chased by a vicious dog who eats the ice cream he drops.
"Him" featured the female cast members under the unknowing thrall of a high school jock (he didn't know he was having any effect on people). At least one result of this is Buffy trying to kill the school principal who'd been giving said jock a hard time. While Principal Wood is working in his office, we see Buffy through his window about to blast him with a rocket launcher before Spike shows up and wrestles it away from her.
Another episode from an earlier season has a conversation between two characters while in the distant background Spike runs from shadow to shadow under a smoking blanket.
In the sixth-season Musical Episode "Once More, with Feeling", Anya, Giles, and Xander walk down a street discussing their inexplicable singing, while around them Sunnydale residents enact various Broadway cliches such as a romantic pas de deux and a trio of dancing chimney sweeps.
In the same episode, when Giles & co. sing the line "Let it Burn" there's firetrucks rushing off in the background. Though remembering the spate of spontaneous combustions going on around the town might make the event a little less funny.
Tara bumps into a pillar during the Summon Backup Dancers at the end. And in the next shot she's fixing her hair and trying to join back in.
In "Selfless", which had numerous flashbacks to Anya's past, there's a scene where she's conversing with D'Hoffryn while in the background the villagers chase around her ex, Olaf (whom she turned into a troll), eventually leading to a large pine tree falling down and crushing a building.
"Who Are You". Buffy is kidnapped by a Watchers Council wetwork team, but is able to grab one as a hostage. The other two tell her to just kill him and walk off. As the wetwork team discuss what they're going to do with their prisoner if she continues to be troublesome, the hostage goes flying out the back of the truck behind them.
In the Season 4 episode "The Harsh Light of Day", the Greek letters on the Frat house Buffy are Gamma Alpha Pi (ΓΑΠ) which, from the angle the shot is taken, look a bit like FAIL. The house in the background across the street bears the letters ΤΩA. Perhaps it's a sorority house?
Also arguably half the karaoke singers in Caritas.
Cordelia is ranting about how insensitive Angel is to her friends' needs, while in the background Doyle is being throttled by a demon tentacle.
Eve and Gunn are arguing in Gunn's office, and through the window we see a literally Ax-Crazy employee stalking towards them holding a fire axe. Just as he's about to swing it at the window, a guard tackles him to the ground. Eve and Gunn turn and see no one there, so go back to their conversation.
Played with on How I Met Your Mother: The gang have gotten up to watch Robin's early morning talk show, and mute it seconds after it starts because Ted has just found out Lily sabotaged several of his relationships. The fact that they're missing what appears to the most awesome episode of that show ever serves nicely as comic relief to the serious discussion in the foreground.
In another episode, Robin has an altercation with a woman outside the restaurant where Barney and Nora are having a date, the whole thing seen outside the window while an oblivious Barney and Nora dine on without noticing it.
In another episode, while Barney is in the office of the laser tag owner discussing his misconduct as a player, they talk about how Barney is one of the best laser tag players the owner has ever seen. If you look in the background you can see a dry erase board for the all time time records for the laser tag arena. Every single one of the records has Barney's name on it.
In The Nanny, Maxwell and C.C. are entertaining backers, while in the background Fran is chasing her sister and husband through the mansion. The three of them eventually realize what they are interrupting and start dancing to the music.
Northern Exposure: during the wedding in episode four, they are not playing the traditional wedding song, but rather it seems to be an organ version of "(I Did It) My Way" by Sinatra.
In The A-Team season one episode "The Beast from the Belly of a Boeing," there is a scene where an airplane crashes into the terminal and a fleeing woman throws her baby (an out-of-tone gag for the series coming from careless use of Stock Footage from Airplane, which has at least one of these in every shot).
Scrubs has done on an irregular basis. Particularly in the earlier episodes.
One episode had JD having a conversation with Elliot, as the Janitor is dressed up like a ghost and is "haunting" the pedriatric ward to prevent the children from making messes.
Stargate SG-1 had its fair share of background funny events, especially through Jack O'Neill, the leader of SG-1. In one episode, as Daniel Jackson explained something extremely plot-relevant and science-ey, O'Neill stood behind him, apparently oblivious, making faces while playing with a magnifying lens, the joke here is that Jackson is describing someone as having the mind of a child, and being very easily distracted, traits that O'Neill is so ably demonstrating. Jackson finally turned around when he realized everyone was looking behind him, but then just rolled his eyes and continued.
Anytime Siler walks past in the background with his absurdly oversized wrench.
Reaper uses this a few times, although the level of subtlety varies; in one example, the main characters lock the door to the big box store they work at in the middle of the day, leaving a huge crowd to mill around like zombies on the other side of the glass, in another, while one character crashes a funeral, the other three can be seen chasing someone around in a slightly slapstick manner behind him.
Happens on occasion in Top Gear. The most notable example is during the "typical seventeen year-old's car" segment, where, while the Power Trio discuss the difficulty in getting their cars insured, the Stig walks in and begins photocopying his head, helmet and all. For no apparent reason (then again, he isthe Stig).
In another episode, while Jeremy is signing off on the homemade motor-home challenge , his motor-home is falling off the cliff behind him. It's amazing.
Earlier, Richard Hammond's motor home catching fire was this until Jeremy finally notices the smell.
Then on The One Show remote control cars (that stick to vertical surfaces) can be seen in one episode driving up the back window, being controlled by mischievous presenters down below as they played with them (Top Gear's offices are directly below the studio where The One Show is broadcast).
Then there is when Clarkson took a Peel P50 around the BBC Television Centre driving around the offices...and then into the background of the BBC News 24 live broadcast..
An episode of Gossip Girl has Dan trying to cook a delicious meal for his movie star girlfriend Olivia. While Olivia is on the phone, Dan can be seen running around in slight panic in the background as smoke begins to rise from the kitchen.
In The X-Files episode "Hollywood A.D.," Mulder and Scully's work is used as the inspiration for a movie starring Gary Shandling and Tea Leoni. At one point Leoni asks Scully to demonstrate how she runs in high heels. Later, while Mulder and Shandling are talking in the foreground, Scully can be seen running back and forth across the sound stage, while Leoni observes.
One of The West Wing's CMOF is this: Charlie and Zoe are arguing outside Josh's office, Josh can be seen in the background. Charlie says: "I work in a building with the smartest people in the world." Cue Josh sitting down on a non-existent chair.
In the first episode of the fourth season, Toby, Josh and Donna end up being left behind after an event in Indiana and on their way to catch their flight they find out that they've already missed it because it went out of an airport in a different timezone. While Donna starts coming up with a new plan with the volunteer who's been helping them out, Josh and Toby storm off to do helpful stuff in the background like shout about the lack of civilisation and hit things with sticks.
"Robot" uses several of these to characterise the new Doctor:
Early on, the Brigadier and Harry are looking at a hole in a chain-link fence, talking about the mystery. Between them, and right at the back, the Doctor can be seen playing with the flowers in the grass.
Later, there's a part where Kettlewell is talking to the Brigadier and the Doctor can be seen sitting right at the back of the frame with a comically intense, sinister expression on his face, lurking in an exaggeratedly creepy manner.
In one scene the Doctor and Kettlewell are conversing seriously in the foreground. At the back of the frame, you can see Sarah Jane cracking up at the Doctor's ridiculous mannerisms, and the Brigadier nudging her to get her to stop.
At one point, Sarah and the Brigadier are discussing the plot while the Doctor is building a tower of random objects for some inexplicable reason, finishing by balancing a pipe on top. At the end of the scene, Sarah notices, gives him a forced smile and it collapses in his hands.
In the series 1 episode "Rose," Rose is briefly seen obliviously making tea while the Doctor is being strangled in the background. (Not that she gets much more concerned once she actually sees it...)
In "The Idiot's Lantern", when asked by a policeman to tell them everything he knows, the Doctor replies, "Well, for starters, I know you can't wrap your hand 'round your elbow and make your fingers meet." In the background you can see an officer trying it out.
In "Closing Time", when a lingerie department assistant calls security on Craig, having mistaken him for a pervert, a man in the background looks up alarmed.
A foreground example in "The Doctor's Wife". When preparing to launch the ad hoc TARDIS console, the Doctor spouts some important plot dialogue, while in the foreground we see Idris!TARDIS examining her new face in a mirror and smooshing it about.
In "The Crimson Horror", after Clara has been revived, the Doctor is shown in foreground having a conversation with Madame Vastra. In the background, slightly out of focus, her wife Jenny can be seen sizing up Clara, with Clara apparently returning the gaze. Funnier if one knows about the UK tabloid rumors that Clara was going to romance either Vastra or Jenny!
Community has Abed in a series of these during the 3rd episode of the 2nd season. It ends with Abed helping to deliver a baby in the parking lot. They do some Lampshade Hanging on it when Shirley asks what Abed got up to. "Nothing much" is the reply.
"Cooperative Calligraphy" has another example. The entire episode focuses on the group attempting to find Annie's missing pen. An early scene (Specifically, during Troy's "Aww, I wanna lick it!" line) shows Annie's Boobs the monkey taking it, but it's very difficult to spot.
A staple on Glee. A lot of the group numbers have to be seen multiple times to catch everything. For example during Forget You Kurt gets chased around the piano by the other guys.
In one episode of Morecambe and Wise Ernie and a woman are singing Somewhere My Love as a homage/parody of Doctor Zhivago all the while Eric was controlling the carriage. Every once in a while he'd tell the horses to giddy-up and gently hit them with the reins, only to be pulled forward off and have to climb up from the back. He changes his position throughout the entire song.
iCarly occasionally does these. One example is in a crowd scene, Sam mentions something about hurting Freddie, and a couple of extras give each other a look of shock and horror in the background.
There was a part of Still Standing where the mother and father were going over their plan to snag some The Who tickets from their friends. While the mother is plotting, we see Tina walk into the kitchen, pick up a cutting knife, then leaves. Her older sister then runs in looking scared.
While Cheers normally puts its humor in the foreground, the episode where the gang makes a video for Woody's parents pulls this twice. The first moment occurs during a backyard barbecue at Carla's house. While she struggles through her lines, two of her kids chase Sam with a garden hose through the background. Later, we see Frasier give a speech in his office. As he sits with his back to the window, he talks about how the building has the best psychiatric help in all of Boston. Just as he says that, a body falls past the window.
A staple of the show Crank Yankers. Sometimes the gags going on in the background were actually funnier than the contents of the calls themselves.
In the first full moon episode of H2O: Just Add Water, Cleo tries to hold a speech for Emma's father because Emma was stuck in mermaid form and was acting like a Cloud Cuckoo Lander due to the influence of the full moon. While Cleo is trying to hold the speech, Zane and Miriam (whom Emma had earlier frozen together by the lips while they were making out) are seen in the background.
The Adventures of Pete & Pete episode "Yellow Fever," in which Big Pete's class gets lost on the way to a field trip, has Bus Driver Stu pull over in to ask for directions, only to find upon further inspection that the farmer he wanted help from was actually a scarecrow. Meanwhile, the main subplot continues on the bus, but look through the bus's windows and you see Stu beating the crap out of the scarecrow.
Pushing Daisies: One episode had the gang investigating murders at a circus. They visit the scene of a car accident where a Clown Car crashed into the water. Throughout their whole conversation, coroners keep walking past with clown bodies. First it's funny. Then it's not. Then it is. Again.
Star Trek: Voyager had a few of these. Once with the engineers discussing the latest technobabble problem while Janeway hunts for coffee in the background (apparently an ad lib on the part of either Mulgrew or the director to liven up boring exposition). Later we have the doctor fuming in mute frustration at having his audio feed cut while the other Voyager crew members discuss their next action.
One example in Tinker Tenor Doctor Spy, at one point an Engineering scene is hijacked by the Doctor daydreaming about a warp-core breach. When the problem is initially detected, there's a dramatic shot of the warp-core smoking. It's faint, but if one listens closely one can hear someone saying "Forget the children, save yourselves!" - hilariously out-of-character for Starfleet officers.
At the beginning of the episode “Monkees Marooned," during a close-up of Peter talking with the salesman, there is a random guy in the background with his arms out like an Egyptian, standing on the bumper of a moving car. The same thing happens again in the tag sequence, but only after the guy and his friends are confronted by the policeman (also in the background). Hilarious and completely unrelated to the episode! Blink and you’ll miss it.
In the music video for “Randy Scouse Git”, while the camera is centered on Micky singing the song, Michael is seen in the background making several goofy expressions, and yawning while playing guitar during the song!
In the J-drama Yamato Nadeshiko Shichi Henge Kyohei looks up videos of belly dancers and shows them to the others, but they move on to discussing a completely different topic thereafter. As it goes on Kyohei is still watching the videos in the background and begins imitating them.
In an episode of The Fresh Prince of Bel-Air, Phil and Will are fighting in the sound room while Ashley and Carlton are fighting in the control room as to whether or not to listen in. The segments where Ashley turns off the sound definitely fit into this with Will's extremely active motions of anger.
Carlton: Oh great! Now we'll never know how Will took the news!
30 Rock uses these pretty frequently. An early example is in the season one episode "Tracy Does Conan," in which Tracy is suffering some strange side effects from his new medication, leading Liz to have to call his doctor for help while behind her, we see a raving Tracy trying to put his shoes in the fish tank and then being rocked like a baby, with thumb in mouth, by Dot-Com in an attempt to sooth him.
In "The Boys' Night Out Job", Eliot beats up a bunch of drug dealers as Hardison tries to scare them into giving themselves up.
In the Jonathan Creek episode "No Trace Of Tracy," Maddie goes to interview a has-been rock star at a recording studio. It's soon discovered that he replaced his previous session musicians with a new crew while the old ones were out getting pizza. The rock star retreats to the mixing booth and leaves his manager to sort out the mess, and the interview is conducted while both Maddie and the rock star, thanks to the soundproof glass, are blissfully unaware that the two bands have started kicking the crap out of each other in the studio behind them.
On an Ellen DeGeneres episode of the fall 2009 season, there is a segment on Kid Inventors. The first invention is by a third grader named Simon who invented a high chair bib for his baby brother Alan with a pully system that can dump whatever food he drops back onto his tray. Two inventions later is an air pump powered by pojo stick invented by fifth grader Ben. While he is setting up his invention and explaining how it works, the camera switches back to Alan who is in the process of dumping his chocolate pudding over his tray.
Used by British-Indian comedy sketch show Goodness Gracious Me in a parody of Indian cinema, with a retrospective of the career of director "Ranjit Say", who keeps claiming that the important themes of his films are present "in the background." The interviewer thinks he means the subtext, but he means the background: All his films consist of the same black and white shot of two men playing draughts, whilst two people passing in the background stop to perform some action appropriate to the supposed genre of the film; comedy slapstick, fighting, a dance routine, etc.
A sketch on MadTV featured Debra Wilson appearing out of character on a talk show talking about the show. Outside, people are fighting a giant ant.
Seinfeld has Jerry and Elaine in a mundane discussion on a couch while Kramer is having a violent seizure from hearing Mary Hart's voice.
Mad Men has the employees of SCDP wheeling around Miss Blankenship's body around on a wheeled chair through the window behind the clients that Don, Faye, and Ken are trying to impress in "The Beautiful Girls" (4.09).
Four episodes earlier in "The Rejected", there's not only Bert Cooper lurking in his own lobby eavesdropping on people's conversations, but when Alison confronts Don over his sleeping with her and then dumping her, throws a glass at his head, and quits, you can see Peggy's head rising over the partition between her and Don's office.
In the second episode of the series there is a scene where Don, Roger, and Cooper stand outside of Don's office and discuss creating a campaign for Nixon while inside the office Ken, Sal, and Kinsey goof around with aerosol cans of Gillette deoderant and create fireballs.
In the first season episode "Shoot", Ken insults Peggy and Pete responds by slugging him. As that goes on, Don and Roger walk by in the foreground, apparently unconcerned.
Happens all the time in Degrassi The Next Generation. That Sean is sitting with Ellie supporting Marco instead of with Jay and Alex is seen as proof of Sean/Ellie shipping, which is even more amazing when you consider that Marco sexually harassed Sean in the show's coming out party. The original Degrassi Junior High would often have you spotting your favorite extras.
There is an episode where at the end of a "Scene to Rap" segments (I think the them was The Exorcist), a woman from the staff comes behind Drew Carrey and serves him a beverage, which was obviously not something that had to be done on camera. It provoked a lot of laughs from everybody present in the studio.
Married... with Children: The Bundys are having a holiday cookout and invite the Darcys. Marcy's bummed about her dead aunt, whose cremated remains she keeps in their house. Said remains end up in Al's grill after Peg spilled the ashes out of the grill. Once Kelly figures out she dumped Marcy's aunt on the grill, Hilarity Ensues in the background as Al consoles Marcy, both completely oblivious to what's going on behind them.
In Castle Season 2 Episode 18, while Beckett is having a rather serious phone call, in the background, Castle picks up a huge hunk of scrambled egg with his fingers, put the entire thing in his mouth, and then chokes on it because it's so hot.
In Episode 5 of Kamen Rider Fourze, while two of the teachers are talking about something, there is a teacher in the back who gets punked by a student. The teacher responds with a Necklock.
The opening credits has a quick montage of Fourze using various Astro Switches, which go by so fast it can be hard to pick out individual ones, but sharp-eyed individuals can see Shield!Fourze flashing a peace sign, and Flash!Fourze blinding himself.
The newest version of the opening adds in more Switches and more gags. Hand!Fourze can be seen playing Rock-Paper-Scissors with the mechanical hand (and LOSING), while Stealth!Fourze, does a Naruto-style hand seal as he disappears, then starts tip-toeing.
More subtly: in many Frasier episodes, there are groups scenes where something plot-relevant is happening in the foreground, while Niles can be seen gazing at or sighing over Daphne in the background. The actor (or director's) commitment to detail is impressive.
An extended one was improvised by Patton Oswalt in the opening to the King of Queens episode "Emotional Rollercoaster": There's a party scene where the whole cast is present but he has no lines or anything else to do, so rather than do any sort of Artificial Atmospheric Actions, he opted to stand perfectly still with a blank expression on his face for the entire three minute scene. It gets particularly funny when the action moves into the kitchen, and you can see through a window to the living room that he's still doing it.
In Episode 4 of The Thick of It, Olly is brought to Number 10 so that Malcolm and Jamie can coerce him into exploiting his new relationship for information on the Opposition. At one point, a staffer behind Olly makes kissy faces at him while he tries awkwardly to arrage a date with the girl. Jamie then rushes over, grabs the guy by the head, and gives him a near-silent bollocking. There are also a couple of instances where Olly is trying to talk on the phone to different people while Malcolm or Jamie loudly berates one of their employees in the background.
Malcolm's Atomic Cluster F-Bomb bollocking of Hugh, only slightly muffled by the transparent office, while Terri fusses over Angela Heaney's tea in the foreground.
And then there's the time Jamie decided to amuse himself and Malcolm by fellating a pen behind Julius Nicholson's back.
Australian sketch comedy show Full Frontal had what ended up being the crew's favorite from the second season. A weather report begins with a time lapse from a building rooftop. As the weatherman begins his spiel we see various things happening, including a repairman falling off the roof trying to repair an antenna... five times.
There's a fair number during the course of Mythbusters; often one of the five will be talking about their build or the experiment in the foreground, while one of the others has things happening in the back.
For instance, in "Bull in a China Shop," Kari comments that she wants to test the foam mockup shelves she's made to ensure that the bulls won't get hurt if they crash into them. Cue Tory taking a flying leap onto one of the shelves right behind her, crunching it into the crash mat, right as she finishes her sentence. She pauses mid-word, but doesn't even look behind her. Tory just lays on the mat and seems to be trying very hard not to burst out laughing.
In "Escape Slide Parachute," Jamie is talking about the airplane slide raft's potential as an improvised parachute. In the background, Adam and Grant are trying to piece Buster back together. Again. For the second time that day.
In "Titanic Survival," Jamie and James Cameron are discussing the atmospheric conditions and temperature of the night of the sinking to allow the Mythbusters to accurately recreate conditions. In the background, a trash can fire burns out of control until Adam appears on the scene and puts it out noisily with a fire extinguisher, much to the bemusement of both James and Jamie.
In the second episode of Elementary, the foreground shows Watson talking on the phone while in the background, very much out of focus, Holmes sets his iconic violin on fire.
"Series/Tosh.0" had a segment called "What's In The Background?"
Why did this family bring a swimming pool to the beach?
On Once Upon a Time, Snow and Emma find themselves talking to Lancelot, the leader of a group of refugees living in exile from the Dark Curse. While the camera focuses on Snow and Lancelot when they discuss their plans of action and other matters, Emma is in between them and out of camera shot making faces at the food offered before deciding that she likes the food.
On Star Trek: The Next Generation, there's an episode where a transporter accident creates a duplicate of Riker. In one scene, the two Rikers confront each other during a poker game. However, the scene is stolen by Worf, who has clearly just been dealt the worst hand in the history of poker.
Rookie Blue's episode "Class Dismissed" has a bunch of teens stealing an umbrella the characters had been previously watching over while said characters kiss.
The Office episode "Beach Games" features Dwight trying and failing to successfully tell "The Aristocrats." Though the event gets a few shots devoted to it, the primary focus is on Pam's efforts to do the coal walk, meaning only the attentive or returning viewer is likely to absorb the joke.
Mr Selfridge has an unintentional one. In the third episode, the drunken Reg Towler gets on a trolley just as it lurches to a start. The trolley's sudden movement is so violent that one of the extras, a woman in a white dress, is slammed against the side of her seat. She rubs her arm and mutters to herself until the scene changes.
In the 2nd episode of the Whose Line Is It Anyway? reboot, during the game "Song Styles", Colin is in the background doing a dance that looks like a mix between a gospel-type dance and jazzhands.
The game "News Flash" is made of this trope, with the field reporter (usually Colin) trying to use clues from the other players to guess what the background event is. The best one is when clips of Colin himself are used.
Monty Python's Flying Circus was known for this. One memorable sketch was the "Dirty Vicar" sketch. The sketch is about a lecherous vicar. In one part, he is groping a female parishioner, and suddenly Michael Palin dressed as a mountain climber (complete with lederhosen) and two butlers run into the room, look around like they suddenly realize that they are not supposed to be there, and run off.
In the episode "Hollywood Babylon" of Supernatural, when Sam and Dean are walking to Stage 9, two cowboys and a horse and three Roman Centurions walk behind them. In addition, the head of a golden idol is being pulled behind a truck, and an astronaut's suit is being pushed on a dolly.
In The Sing-Off, after the first elimination in the first episode of Season 3, while the host (Nick Lachey) is introducing the next four musicians, Shawn Stockman and Ben Folds start waving and posing for the camera behind him.
When Andrew Zimmern went to Chile for Bizarre Foods with Andrew Zimmern, he did his usual introductory bit with a crowd of Chilean city-dwellers walking behind him. A few people turn to look toward the camera to see what's going on, including a little girl in pigtails who becomes so fixated at the camera and excited about the possibility of being on TV that she energetically waves hello... before almost running into a young man in a wheelchair. Oops.
In House of Anubis, while Jason is describing the acting exercise of using subtext to make the words "I love you" have different meanings, and Jerome and Mara are talking, Fabian and Mick can be seen in the background quickly backing away, and then later awkwardly doing the exercise.
In another episode, while Patricia and Eddie are having a small argument, Sibuna's shocked faces in the scene make it hilarious. The fact that they all react in perfect unison sells it.
JAG: Harm gets quick-and-harsh training in "Force Recon" so he can go undercover as a Marine gunnery sergeant. This training takes place in his salty trainer's yard, and in the background throughout you can see the neighbors looking over the fence and reacting incredulously.
Waktu Rehat: The background scene which showed Wai Chong over-reacting after trying a curry puff in season 1, episode 5.
In the last scene of Alice (2009), Alice and Hatter are reunited and make out. In the background, Alice's mother stares at them and is clearly thinking, "What the Hell is going on?"