Pantomime

Slapstick comedic play aimed at children and shown at Christmas time. A British tradition that (as with most British traditions) baffles Americans; America used to have a somewhat similar tradition in Vaudeville, minus the association with Christmastime, but it died out around the turn of the twentieth century. Referenced throughout British culture, of course. They are equally popular in Ireland.

Pantomimes are based on a relatively small pool of basic stories, mostly fairy tales and mostly Public Domain. These include
 * "The Babes in the Wood"
 * "Cinderella"
 * "Jack and The Beanstalk"
 * "Snow White and The Seven Dwarfs"
 * "Sleeping Beauty"
 * "Aladdin"
 * Peter Pan
 * "Dick Whittington"
 * Robin Hood
 * Mother Goose rhymes
 * "Little Red Riding Hood"
 * Robinson Crusoe

Pantos are traditionally Theatrical Productions, but quite a few have been recorded for Live Action Television, such as The ITV Panto.

Not to be confused with miming things (as in Enemy Mime or Mime and Music Only Cartoon), which is what "pantomime" means in America.

Tropes of the Panto:

 * Much crossdressing, specifically,
 * The Dame, played by a middle-aged male actor in quite heroic quantities of dresses, makeup and enormous fake boobs. Often the most popular and publicised member of the cast. Usually the mother/aunt of the Principal Boy (see below); two dames are used to play Cinderella's ugly sisters.
 * The Principal Boy. Sometimes the titular character, (eg, Jack or Aladdin), often a straight-man to the Dame. The principal boy is traditionally played by a young female actor as if they had escaped from the pages of Enid Blyton. Traditionally slaps her thigh a lot. These days, professional pantomimes will often have a male Principal Boy so they can hire a teenybopper soap actor/pop star to draw in the crowds.
 * It's somewhat debatable whether the Principal Boy, when female, really counts as "cross-dressing". She tends to wear a costume mainly composed of a leotard, fishnet tights, and high heels, and looks significantly more feminine and sexy than the Principal Girl.
 * The Principal Girl, always young and full of wholesome charm. She will fall in love with the Principal Boy, or a Prince Charming if there is no Principal Boy.
 * Pantomime Villains, Dastardly Whiplash types straight out of Victorian melodrama. Black goatees, cloaks, canes, top hats, devilish laughs. Played with delicious relish -- it's the part every actor wants. Green lighting is usually present.
 * See Alan Rickman's performance in "Robin Hood: Prince Of Thieves" or Gary Oldman in "The Fifth Element" for movie examples, though these are both understated and subtle compared to a proper panto villain.
 * Anyone familiar with the career of Brian Blessed knows that he's absolutely perfect for such roles.
 * Audience Participation. In particular, a villain will be stalking a hero around the stage, requiring the audience to holler "HE'S BEHIND YOU!" at the tops of their voices. Usually, the villain will duck behind cover as the hero exaggeratedly looks around, then looks back at the audience and says "Oh, no he isn't." The audience dutifully hollers "Oh, yes he is!" in response. This can go on for some time.
 * In particular one character will have No Fourth Wall, the rest of the cast will only lean on it heavily.
 * This also seems to happen whenever a panto actor appears anywhere in front of an audience: British audiences are prone to collectively getting into spontaneous "No he isn't"/"Yes he is" routines with well-known panto actors even during talk shows, quiz shows, panel shows, and other shows utterly unrelated to panto. (See Christopher Biggins' two-minute appearance on The Big Fat Quiz Of The Year.)
 * Any good panto will leave a pause for the regular jokes. "I didn't come here to be insulted!" (pause) Audience member(s): "Where do you usually go?" If the audience doesn't say the necessary line another cast member will.
 * People are expected to loudly boo and hiss whenever the villains are onstage.
 * Sing Along. Usually at the end, the victorious heroes will teach the audience a song. Often the audience will be split in half and ordered to compete against each other. This virtually always ends with something along the lines of 'For the first in Panto history, it's a draw' to avoid hurt feelings on either side.
 * The Pantomime Animal, usually a four-legged creature such as a horse or a cow played by two actors in an animal costume.
 * The Harlequinade: A slapstick intermezzo featuring characters from the commedia dell'arte. Nowadays, it's usually replaced with some Scooby Doo slapstick with
 * Shout Outs Usually prior to the sing-along. Basically, someone in the cast takes the opportunity to read out the names of the groups in the audience. There's always a Scout troupe or Boys'/Girls' Brigade.
 * Or they'll use material from other notable comedy acts, preferrably older for the adults to recognise and the kids to enjoy. Such as Morecambe and Wise's version of "I'm Wishing" for any Snow White shows.
 * Also, expect a lot of Actor Allusions
 * Sweeties: treats are often thrown into the audience from the stage at some point (again, often at the end). In my home town, these are traditionally Wagon Wheel biscuits. Never having caught one at a panto can be a source of minor childhood trauma.
 * Sadly, this tradition is being phased out in many places because of Political Correctness Gone Mad. Some shows will have a variation e.g. in Aladdin where Widow Twankey might throw comically oversized laundry into the audience instead.
 * Big production - even the smallest amateur company will pull out all the stops for their pantomime. This is not a genre concerned with either realism or artistic minimalism. Sets are large and elaborate, the dame will usually have the most magnificent over-the-top dress (and change it every couple of scenes) and there is often a scene involving gunge, foam or other "messy" fun. Aladdin often features a scene in the Chinese laundry run by Widow Twanky, providing an excuse for filling the stage with suds. Or characters will randomly decide to do some baking, resulting in flour being thrown.
 * Guest stars - a more recent trope dating back to the late 19th Century in the UK, whereby if more than one major panto is running in a town, they will often compete for custom by playing one-upmanship with the quality of the cast. Once the realm of respected actors (and Sooty), this particular aspect took a bashing during The Eighties and The Nineties when soap actors, Wolf from Gladiators, reality TV stars and Frank Bruno all decided to get in on the act; fortunately, most theatres seem to be a little more discerning nowadays, but the occasional Big Brother contestant still slips through the cracks. This can be very lucrative work, which is why Australian soap actors decamp en masse to England in time for the season. Julian Clary, Christopher Biggins, Brian Blessed and John Barrowman are guaranteed to be in panto every single year. We've even taken the liberty of getting a few actors from across the pond, including Henry Winkler, Dirk Benedict and David Hasselhoff. Yes, really.
 * A more recent variant is the casting of an actor with impeccable dramatic credentials (such as Sir Ian McKellen) as a Dame or another minor character.
 * In some productions, the guest stars can turn into the Spotlight-Stealing Squad, but only if they have the skill necessary to hold the audience's attention.
 * Local and topical in-jokes. Some pantos have a script written specially each year. Others are available pre-written with [insert topical joke], [insert local joke], [insert name of celebrity famous for being fat] written in. Often jokes are at the expense of an area of the city known for being posh, or run-down; or a rivalry with a local town (see Springfield v Shelbyville).
 * In many of the panto Stroke Country, the in jokes normally mock the football team The Crusaders (normally by commenting on their consistently bad performance much to the chagrin of nearly ever Crusaders supporter in the audience) or mocking our accent. One such instance had the pantomime Dame mocking the fact that we say 'more' as 'moor' much Hilarity Ensued.
 * Innuendo. While Pantomimes are ostensibly aimed at children, much of the humour is composed of sexual innuendo intended to go over the children's heads. ("I do declare, the Prince's balls get larger every year!") Presumably, this is to allow the adults who accompany the children to enjoy it as well.
 * Periphery Demographic features heavily here. It isn't unusual to find works outings booked to Panto with nary a child to be seen. Frankly half the people there with kids have only dragged them along as cover.