Festival Episode

Japan has a number of traditional holidays which are celebrated with festivals (matsuri) that bear a slight resemblance to American fairs and carnivals (only with a distinctly Asian flavor, of course). Most matsuri are based near or on the grounds of a local shrine, having grown out of local religious traditions—not that it necessarily shows all that much in the modern form.

In anime set in Japan (or in locations with a strong Japanese influence), it's common to have at least one episode featuring one of these festivals. It takes the cast out of their usual situation/locale and puts them in a new one, which usually provides insights and new angles on them. The relaxed yet structured atmosphere of the traditional festival—and the opportunities it provides—can also prompt the evolution of relationships which might otherwise be stalled or failing. And in modern settings, it's an excuse to get the characters—even foreigners—out of modern "Western-style" clothing and into proper kimono and geta, which has a strong appeal to a fair-sized fraction of the Japanese audience.

In some series the resident crossdressers will still wear the appropriate outfit of the other sex.

You often see the Goldfish Scooping Game and Kimodameshi at festivals.

See also School Festival. Compare Christmas Episode and A Fete Worse Than Death.

Some of the festivals you're likely to see in anime:
 * December 31-January 1—New Year's Eve and Day
 * March 3—The Doll Festival
 * (variable, April) -- Cherry Blossom (Sakura) Festival ("Hanami", literally, flower viewing)
 * "Golden Week" -- the end of April through the beginning of May, when a number of national holidays occur, including Children's Day (May 5), the Iris Festival, the Tango Festival, Greenery Day and the Constitution Memorial Day
 * July 7 -- Weaver Fest, also called the Star Festival and Tanabata
 * July 15 or 16—Toro Nagashi, AKA Lantern Floating Day
 * September 9 -- Chrysanthemum Festival
 * November 15 -- "7-5-3" Festival
 * Late December—Year-end Fair

Anime and Manga

 * Shakugan no Shana. "It's a school festival. It's a festival organized by the school."
 * Sailor Moon includes a festival organized by Rei in the second season, as well as a Sakura Festival episode. In a later episode, there is a Lantern Floating Festival, probably. Finally, in the manga, the Tanabata is the focus for one side story.
 * Love Hina has a Festival Episode about two-thirds of the way through the initial series; the manga shows several.
 * A festival helps cheer up Ranma when he is stuck in female form during the "Cat's Tongue Shiatsu" arc of Ranma ½.
 * The anime has a Festival Episode involving a panda doodle with a crush on Ranma.
 * Sakura Taisen puts its multinational cast all in kimono for a festival early on in the first OVA series.
 * My-HiME subverts this somewhat, in that the "Festival" is something much, much darker.
 * Genzo and Megumi spend most of the Tenshi na Konamaiki Festival Episode on the run from the police.
 * Blue Seed actually has a Festival Episode Grand Finale.
 * Subversion: The sinister Watanagashi festival in Higurashi no Naku Koro ni is the central event in The Rashomon style story, told from a number of different angles that end in brutal murders.
 * Kamichu!! had a lot of festival episodes, most in Yurie's honour.
 * The Big O features a Christmas episode in which the hero unsuccessfully battled a giant mutant Christmas tree called Demon Seed.
 * One of the most important parts of Elfen Lied takes place in a festival of this kind.
 * AIR uses flashbacks to festivals in the girls' backstories, and The Movie culminates in a summer festival.
 * Mermaid Melody Pichi Pichi Pitch uses one early on in the summer, and the manga has a few more, usually New Year's things.
 * Episode 8 of the Ichigo Mashimaro anime and episode 27 of the manga have Nobue escort the four little girls at the summer festival. In both, Ana is lacking a yukata, so Nobue "borrows" one off of Miu, who ends up wearing Nobue's old one.
 * Episode 5 of Lucky Star features the characters going to a festival. Konata observes how if this was a Dating Sim it would trigger an Event Flag, seeing as they are wearing yukata and outdoors. Kagami also manages to scoop a goldfish.
 * The "7-5-3" is mentioned by Kagami when she says that Konata wearing a long-sleeved kimono to her coming-of-age ceremony would look like she's celebrating that, instead.
 * Also, Golden Week is mentioned; Tsukasa and Konata fritter it away instead of finishing homework, while Kagami is almost done by the time it's almost over. And in the OVA, while the Hiiragis and Konata go off on vacation, Kuroi-sensei gains several levels in an MMORPG...
 * The Izumis do their first shrine visit of the year (following a day at Comiket that was quite harrowing for the twins, who have to work as miko at the shrine that evening) and draw opposite fortunes. Of course, one of Soujirou's reasons for going was to see the miko...
 * And the four go for Hanami, where they discuss the disparity between what you feel like you should be able to wear and the reality, and Kagami's plump goldfish; Konata asks Kagami if she's going to scoop up a skinnier replacement (she didn't realize, as she was thinking, that she was facing the appropriate booth for it).
 * And again; but first, when Konata wants to show exchange student Patricia some Japanese culture, she calls Miyuki, who says they just put away their princess dolls, but suggests inviting her to a flower-viewing party. Patricia's mind automatically goes to the drinking and eating aspect.
 * Risa Koizumi first confesses her love to Atsushi Ootani while watching fireworks at a festival in Lovely Complex.
 * The "7-5-3"-festival is referenced in the song played during Kozue's duel in Revolutionary Girl Utena.
 * Yotsuba&! features the eponymous Yotsuba learning about display fireworks at one of these; she also plays the Goldfish Scooping Game and wears a yutaka that is just so goddamn Moe it's mind-breaking.
 * In a later festival episode for a local shrine, Yotsuba is happy in a happi as she helps pull a portable shrine through the streets.
 * This Ugly Yet Beautiful World Obon festival, to be more precise. Made plot festival since it is during this festival which people honor the deceased that Hikari first comes to understand death.
 * Azumanga Daioh sends the girls to a summer festival, and highlights that out of the 8 of them, only two actually knew how to put a kimono on. And those two aren't the teachers who were along. One of the few times goldfish scooping isn't shown (although they talk about it). They do see a turtle game of some sort; Osaka asks if a turtle's really needed.
 * Also, they go for their first shrine visit of the year, during which Chiyo makes a special prayer for all her friends to pass, and Tomo draws a bad fortune. Later, Yukari reveals that the shrine owner's son didn't get into college.
 * The last Sound Stage of Magical Girl Lyrical Nanoha A's takes place in a Hanami Festival that nearly the entire cast attends.
 * Kashimashi: Girl Meets Girl has a festival episode that serves to heighten the tension between the all female Love Triangle. Bonus points for having the whole cast wearing yutakas, even the tomboyish girl.
 * They have had quite a few different summer festival chapters in the manga. However,none of these festivals really do anything to the hardly visible tension in the manga.
 * The last episode of Natsume Yuujinchou revolves around a festival that the entire cast attends.
 * In Hidamari Sketch, the Festival Episode has a backstory about Kitsune.
 * Yamazaki is asked to go to a festival by a girl in his school in Welcome to The NHK. He initially dismisses it, due to a childhood memory of seeing a girl he liked with another boy at a festival, but in the end, ends up going.
 * The cast visits a festival in Sayonara, Zetsubou-sensei, and meet a group of people with a penchant for hyping anything. They end up taking several students on platforms and chanting their prominent features. Including "Normal" for Nami.
 * There have actually been numerous festival episodes, including a Tanabata episode in which Kafuka convinces everyone that the wishes they hang on bamboo trees will come true in the next life. (Which ends predictably for Nozomu). Another episode has aliens invade during a festival, forcing a Giant, Kimono-Clad Chiri to fight them off.
 * Damekko Doubutsu had one of these.
 * Ninin ga Shinobuden had one of these in episode 5.
 * Mahou Sensei Negima has both a festival episode (the summer festival) and a festival arc earlier.
 * That arc lasted around 7 volumes.
 * Part of the second episode (and the third, and the fourth, and the fifth...) of Suzumiya Haruhi Season 2 takes place during the O-Bon festival and the group, among other things, plays with fireworks. Yuki buys a mask.
 * Also, the first episode happens in Tanabata time (well, except the part Mikuru sends Kyon back in time with her).
 * Both versions of Asatte no Houkou have one of these. They both advance the plot, but in slightly different ways.
 * The Pokémon episode "The Ghost of Maiden's Peak".
 * And the Twinleaf Festival miniarc in Sinnoh.
 * At the end of the first arc, Fushigi Yuugi features the fictional Stargazing Festival, which Miaka attends with Nuriko and Tasuki.
 * Black Lagoon: Rock and Revy attend a street festival towards the end of the second season.
 * Karin has the typical school festival arc.
 * Canaan begins its first episode with a variation of this trope. As the show opens up in Shanghai, the festival has a distinctly Chinese flavour.
 * Hayate the Combat Butler has a festival happening at Riza's house, the characters continually mention that it doesn't resemble a shrine festival.
 * Episode 19 of Keroro Gunsou has the frog invaders running a series of stalls as part of their latest scheme to raise invasion funds, and Natsumi getting them to leave by meeting their turtle-catching challenge. It even featured a new ending credits sequence with a new song, "Pekopon Invasion Ondo"
 * Ouran High School Host Club has a festival chapter in the manga. A few chapters prior to this a new female character named Yasamura Mei was introduced. The boys, Haruhi, and Mei attend a local summer festival in Haruhi's area and all are wearing proper yukata. Much to the boys' delight, Haruhi was wearing an exceptionally beautiful yukata made by Mei (who was more than happy to brag about how well it turned out).
 * In Great Teacher Onizuka, upon finding that a matsuri is going on at a local temple, Anko suggests to Noboru that they check it out. She uses it as an excuse to change into her yukata and spend the evening with him without actually calling it a date.
 * Seto no Hanayome has one of these early on; with the added twist that San's family has taken over most of the booths with the intent of killing Nagasumi, using such methods as putting a shark in the Goldfish Scooping Game.
 * There's a horror manga titled Tanabata no Kuni which involves the traditional festival of a Town with a Dark Secret.
 * Chi's New Address has Chi visiting a festival with Tama.
 * One of the early levels in Osu! Tatakae! Ouendan takes place at a matsuri, and involves a dude challenging his crush's father to a mikoshi race.
 * Episode 7 of Tenchi Universe, which included Ryoko manning a Goldfish Scooping Game - with fish the size of minivans - and Washu testing out a fun house that lead to a variety of dangerous landscapes, including a field of crystal and the surface of a star.
 * Ghost in the Shell: Innocence has Batou going into New Port City, which might be located in China (it has very distinct Chinese atmosphere). And a festival/carnival is going on, it's like something you can expect in local chinatown during certain time, but... Mind Screwier. For starter, everything seems HUGE, including the statue/balloon/hologram of Guan Yu that's being paraded around town.
 * THE iDOLM@STER - The first time the girls go on stage is during the Summer Festival at a rural village.
 * The closing credits for the last episode of the first season of Squid Girl sees some of the characters at a Bon festival for a few seconds.
 * In K-On!:
 * The second and third years, the girls have a New Year's party at the Hirasawa residence. It matters not that the one for their third year was unplanned; Ui was just as prepared.
 * For their first and second years, they make their first shrine visit for each. The first year, Ritsu tricks Mio into dressing in a lovely kimono, while Tsumugi manages to come in normal clothes. These roles are reversed the next year. Also, for the second year, Ritsu receives New Year's cards from the others, and decides to make hers into substitute omikuji.
 * Rance Quest has a sports festival event for Autumn.

Live-Action TV

 * Almost all Super Sentai series have an episode like this (usually for New Year or Tanabata).

Video Games

 * Persona 3 and Persona 4, taking place in the year in the life in the protagonists, has a Summer Festival. It's nearby the local shrine and you can choose who to hang out with. The male protagonist of 3 has a selection from his school love interests, Portable has the female protagonist choose from her fellow members of SEES. 4 has a notable example in that the entire Investigation Team (plus Nanako and Dojima) have a day to themselves and then a day for the protagonist's school friends.
 * Also a festival in the past is a BIG plot point in Persona 2 Innocent Sin

Western Animation

 * Western Example: In an episode of the Asian-influenced animated series Avatar: The Last Airbender, the protagonists briefly attend a cultural Fire Nation festival. The festival itself was primarily based on Chinese New Year festivities and the masks that were worn by the characters were based on Kabuki theater. They also saw a children's puppet show of Fire Lord Ozai setting an Earthbender on fire.