Twenty-Four-Hour Party People

When TV characters hold a birthday party or baby shower or a similar event, the party will be attended by four or five familiar characters, as well as about twenty people who have never been seen before and will never be seen again. Since we see pretty much every aspect of the characters' lives, we can't help but wonder who these people are and when the characters had time to befriend them. Strangely, by the time of the relevant character's next birthday, they've completely changed around their extraneous circle of friends. Also, rarely will the main characters ever interact with these people at the party, unless it's just for a quick throwaway joke.

This is especially common in sitcoms.

Not to be confused with the movie 24 Hour Party People, a Biopic of Factory Records and the Manchester music scene in the 1980s/1990s, though both the trope and that movie are named after the Happy Mondays song.

See also New Neighbours as the Plot Demands and Social Circle Filler.

Film

 * In the infamous "So bad it's good film" The Room, the latter part takes place at a birthday party Lisa throws for Johnny. The party is full of people that the audience has never seen before but the kicker is the character of Steven who has never been introduced up until that point and somehow is involved enough in the plot to give counsel to the main characters. (The character was actually supposed to be another character that was introduced previously, but that actor and the infamous Tommy Wiseau got into an argument, resulting in Wiseau firing him and replacing him with the other actor, hoping no one would notice.)

Live-Action TV
"Barney: Hi, have you met Ted? Random Girl: No. Barney: Do you know Marshall? Lily? Random Girl: No. Barney: Hmm. Do you know anyone at this party? Random Girl: I work with Carlos. Barney: Excuse me. (to Ted, Marshall and Lily) Barney: Anybody know a Carlos? (they shake their heads)"
 * Friends is particularly guilty of this. We saw a lot of the six main cast members, and they pretty much exclusively hung out with each other and possibly whoever they were dating at the time. Virtually every party they held was attended by a very large cast of unknowns.
 * Lampshaded when Rachel and Phoebe throw a engagement shower for Monica and invite everyone in her address book who could make it on 24 hours notice. Phoebe's response: "Who the hell are all these people?"
 * Gunther usually was at their parties as well. Lampshaded when one of them is planning a party and says they have to invite Gunther since they've been talking about it loudly in the coffee shop.
 * Used by Reese in Malcolm in the Middle episode "Lois's Sister." Other episodes explain that Reese just invites random people to any party since he has no friends, being a Jerkass.
 * Happens on How I Met Your Mother when Ted's 30th birthday party on the rooftop has dozens of guests.
 * Also hilariously lampshaded in the first season when Ted throws a 3-day party just for the sake of hooking up with Robin again:

"Random Girl: (behind Barney) Hello, Barney. Barney: Of course... Random Girl: You look well. Isn't it weird they invited both of us? Barney: Who? Who invited you, no one even knows who you are! Random Girl: I understand, you're hurt, but... you don't have to be cruel. Carlos was right about you. Barney: Who Is Carlos!?"
 * And the lampshading and the hilarity continues when they meet at the following party:


 * Happens in the KateModern episodes "Charlie's Party" and "Raise the Roof."
 * Lampshaded in Queer as Folk's first season, when Michael has a birthday party attended, apart from his close friends, by dozens of strangers. Brian explains that in order to have any kind of crowd he had to open up the invite list to his own past sex partners.
 * This happens a number of times in House, although in this case, it's more or less justified; it's a hospital drama, and therefore the show is 90% set in a work environment.
 * In one episode, Cuddy has a christening for her adopted drug addict baby, Cameron, Chase and Wilson show up. Along with about 20 randoms no one has seen before.
 * Chase's bachelor party was also attended by people nobody had seen before and never saw again.
 * Justified on Roseanne. When the family throws a party celebrating having won the lottery, it gets increasingly bigger to the point that Dan has no idea who he was just talking to. Obviously, the partygoers were strangers trying to be friendly to get a piece of the money.
 * Almost sent up in Peep Show, where Mark calls out three party crashers to, erm, a bunch of Twenty-Four-Hour Party People. So near, and yet so far.
 * Occurs on Amen. Thelma is having her wedding shower at her house. The Hettabrink sisters and Inga are there, but then there are about 15 other women, supposedly Thelma's friends and fellow church members, that we have never seen before and never will again.
 * Happens in Monk whenever the whole police department is gathered, remarkably at Monk's surprise birthday party.
 * Also The Big Bang Theory, on occasion of Leonard's birthday. Partially justified by the fact that Penny was the one actually organizing the party.
 * Will and Grace also does this during Jack's birthday.
 * Subverted in the Buffy the Vampire Slayer episode "Dead Man's Party." The point of the episode was to have a big party, with a bunch of people at it that Buffy didn't know.
 * One exception to this was Saved by the Bell. Though the main crew was always together, we typically saw the same extras whenever there was a pep rally, party/dance, or class.
 * Happened at Scully's baby shower on The X-Files, though since Scully has no female friends other than one seen in season one and she looks visibly awkward, it's plausible that they're a mix of co-workers and women her mother knows.
 * Played with on an episode of General Hospital. Carly's mother organizes a bridal shower for her. Although the women present are known to the viewers, they are virtual strangers to the bride-to-be, who has no friends thanks to her nasty personality. Adding insult to injury, they've brought gifts not for her, but for her infant son.
 * Sex and the City may have been just as guilty of this as Friends. Anytime the girls hosted a birthday party, baby shower, wedding etc.; most of their guests were a bunch of random characters that were never seen before and would never be seen again for the rest of the series. Keep in mind that when these girls went out to parties, only the four of them attended together about 90% of the time. Their dates were there for the following 10%. Just how good were these friends they kept inviting?
 * Done a few times on Charmed. First with Piper's baby shower and later would be done for every birthday party Piper's children had.
 * You could probably also count Prue's funeral and.
 * Played with in an episode of Fresh Prince of Bel Air. Will's friend Jazz is getting married with Phil performing the ceremony. Will comments on the number of guests who showed up and Phil says "Are you kidding? I hired these people. Jazz ain't got no friends!"
 * Justified in an episode of The Drew Carey Show: Drew plans to invite a few people from work over to his house to drink up the last of his homebrew beer. Mimi pranks him by putting his flyer in the weekly Winfred-Louder newspaper stuffer, so he ends up with practically all of Cleveland in his house - including Special Guest Stars Joe Walsh, Little Richard, and Cleveland's then-mayor.
 * Lightly averted on Freaks and Geeks. In the Beers And Weirs episode's house party, most of the people attending aren't directly friends with Lindsey, but we can assume enough word got around about it that several non-Freak/geek classmates decided to attend (anything for some free beer!). Also, there are quite a few side characters at the party (such as Mark, who would later be revealed as Nick's pot dealer).

Western Animation

 * A notable exception is The Simpsons, which has so many characters now that any gathering will consist entirely of people who were featured in at least one past episode (although it may be completely ludicrous for them to attend the gathering in question). In fact, The Simpsons has random extras instead of Faceless Masses.
 * It's not that unusual for an animated show to have its party people to be the same at every party. After all, you only need to draw these characters, and they don't necessarily have to have any lines. In a regular, non-animated sitcom, you would either have to hire the same group of extras for every party, or only use crew members and friends of crew members as background talent.
 * Lampshade Hanging occurs in the Rocko's Modern Life episode "The Big Answer." Two random background characters show up as guests at Filburt's bachelor party. When Filburt asks who they are, Rocko realizes he doesn't know either.
 * Happened twice in SpongeBob SquarePants.
 * Also happened again in the episode when SpongeBob is rich.
 * That one is justified, as they were just rich people attracted to Spongebob's sudden wealth.
 * In the Beetlejuice cartoon, the Neitherworld literally sells these. In cans. Needless to say, when Beetlejuice buys some, it does not end well.