Happy Festivus! All About the “Seinfeld” Holiday for Airing Your Grievances (Plus 8 Other Fictional TV Festivities to Celebrate Year Around!)

There's always a fun celebration to observe throughout the year

National holidays are great — but these fictional TV festivities are better.

For decades, TV writers have been thinking up new (and odd) ways for their characters to celebrate life year-round. Fictional holidays like Seinfeld's Festivus and The O.C.'s Chrismukkah paved the way for festivities such as Galentine's Day — which originated on Parks and Recreation in 2010 and is widely celebrated today.

"It sort of took off. We did it once just because we liked the idea of it, and then it just became this thing that people locked into," Parks and Recreation co-creator Mike Schur told LAist in 2019 of the fictional holiday centered around "ladies celebrating ladies."

So while the holiday season is nearing the end with Christmas and New Year's Day, there are still other special occasions to look forward to.

Here's a list of the most memorable fictional TV holidays to add to your calendar.

Festivus, 'Seinfeld'

Festivus was introduced by Jerry Stiller's Frank Costanza during a Seinfeld episode in 1997. It takes place on Dec. 23 each year.

Also known as "a Festivus for the rest of us," the holiday was created for those looking for a Christmas alternative to avoid the pressures and commercialism of the season.

Ways to celebrate include Airing of Grievances, Feats of Strength and recognizing easily explainable events as Festivus miracles.

Airing of Grievances happens immediately after dinner is served, where everyone at the table vents about how they've been disappointed in the past year.

Feats of Strength occurs after dinner, where the head of the household challenges one person to a wrestling match.

Oh, and don't forget to trade in your decked-out Christmas tree for an unadorned aluminum pole!

Galentine's Day, 'Parks and Recreation'

Galentine's Day was first introduced by Amy Poehler's Leslie Knope during a Parks and Recreation episode in 2010. It takes place on Feb. 13 each year.

The purpose of the holiday is to recognize and honor the relationships shared with female friends ahead of Valentine's Day.

Ways to celebrate include throwing a boozy, waffle-filled brunch and exchanging gifts with gal pals only.

As Leslie put it, "Every Feb. 13, my lady friends and I leave our husbands and our boyfriends at home, and we just come and kick it, breakfast-style. Ladies celebrating ladies. It's like Lilith Fair, minus the angst. Plus frittatas."

Chrismukkah, 'The O.C.'

Chrismukkah was first introduced by Adam Brody's Seth Cohen on The O.C. in 2003. There's no exact date for this holiday, but it lasts nine nights.

The hybrid name is a combination of both Christmas and Hanukkah. Chrismukkah was created as a way to enjoy the best of both holidays.

Ways to celebrate include "eight days of presents, followed by one day of many presents," as described by Seth on the show.

Merlinpeen, '30 Rock'

Merlinpeen was first introduced by Judah Friedlander's Frank Rossitano on 30 Rock in 2009. There's no official date for this holiday, but it happens around Christmastime.

It was created to coincide with the Pranksmen's fake religion called Verdukianism to opt out of Kenneth Parcell's (Jack McBrayer) Secret Santa.

A way to celebrate includes leaving work early on Merlinpeen.

Verdukian beliefs features "the healing power of root beer" and "that a man can have up to nine wives if two of them are male," according to characters on the show.

Another holiday celebrated within the fictional religion is the Verdukian Holiday of Mouth Pleasures, which includes indulging in free sausage pizza.

Slapsgiving, 'How I Met Your Mother'

Slapsgiving was first introduced as the title of a How I Met Your Mother episode in 2007. Fans might choose to pass on this celebration, but it takes place on Thanksgiving each year.

It was created when Neil Patrick Harris's Barney Stinson lost the slap bet, giving Jason Segel's Marshall Eriksen five slaps to be administered to Barney at any time he desired. Though not a fun holiday for the slap recipient, the comedic episode is an enjoyable one to watch.

Ways to celebrate include choosing a Slapper by the Noble Slap Master, creating a slap countdown to the big event and cutting out hand-shaped paper turkeys. It also has an official song.

It's a day filled with slap-atizers and pumpkin pie!

Leap Day, '30 Rock'

Leap Day turned into a substantial (fictitious) holiday when it was first introduced by Alec Baldwin's Jack Donaghy's on 30 Rock in 2012. It takes place on Feb. 29 every four years.

The holiday derives from Jack's dream sequence after he eats rhubarb leaves and is visited by a gilled creature named Leap Day William, who surfaces from the Mariana Trench to trade in children's tears for candy.

Ways to celebrate include eating slices of rhubarb, trying new things, wearing blue and yellow and living by the motto that nothing on Leap Day matters because "real life is for March!"

Treat Yo' Self Day, 'Parks and Recreation'

Treat Yo' Self Day was first introduced by Aziz Ansari's Tom Haverford on Parks and Recreation in 2011. It takes place once a year on Oct. 13.

Considered the "best day of the year," Tom and Retta's Donna Meagle make an entire day out of splurging and indulging on foods, activities and purchases that make them happy.

Ways to celebrate include treating yourself to clothes, fragrances, massages, mimosas, fine leather goods and eating sushi formerly owned by celebrities — like the two do on the show.

Ludachristmas, '30 Rock'

Ludachristmas was first introduced by the cast and writers during an episode of the same name on 30 Rock in 2007. There's no official date when this holiday takes place, but it happens around Christmastime.

Every year, The Girlie Show staff holds a highly-anticipated, company-office party ahead of the holidays. The party is legendary for its drunken festivities and trashing of company Christmas gifts.

Ways to celebrate include hiring a stripper, throwing away useless gadgets (like photo scanners and paper shredders) and letting loose in a booze-clouded bubble before returning home for the holidays. It's a time to release office-related frustrations in a safe, Christmas-sweater-wearing way.

Best Friends Day, 'SpongeBob Squarepants'

Best Friends Day was first introduced as a fictional holiday during an episode of SpongeBob SquarePants in 2007. It takes place on Feb. 19 each year.

The day was created to recognize and honor the relationship formed between friends. On the show, Patrick Star celebrates his friendship with SpongeBob through the gift of gum.

Ways to celebrate include giving your friends gifts you think they'll treasure rather than something you enjoy yourself. (Patrick did not get this right the first time, giving SpongeBob a giant ball of chewed-up gum he thought was disgusting.)