You know Christmas, Hanukkah and Kwanzaa and maybe Yule and Hogmanay too. But do you remember any of the more recent holidays that originated from a sitcom?

The secular holiday Festivus takes place on December 23rd and has been celebrated by fans of the series “Seinfeld” since the 1997 episode “The Strike.”

“The Strike” first aired on December 18, 1997 and features an interaction between Jerry Seinfeld’s neighbor Kramer and George Costanza’s father Frank. It’s about a holiday that Frank invented after trying to buy “a doll” for his young son.

An argument between Frank Costanza and another man, who also reaches for the doll, ends with the doll’s demise and a revelation.

“A new holiday was born,” says Frank Costanza Kramer. “A Festivus for the rest of us!”

Customs include a bare aluminum pole – “tinsel distracts me,” said Frank Costanza, along with airing grievances and heroics.

When the celebration occurs at the end of the episode, it’s neither a spoiler nor a surprise (given past experiences) that George can’t surpass his father in feats of strength.

Of course, the episode’s airdate conflicts with the typical day Festivus lands.

When Kramer returns to work at a bagel shop after resolving a year-long strike, he asks his manager to take December 23rd off for Festivus. His manager rejects the request, prompting Kramer to go on strike again and sabotage the store before eventually returning to work and being fired.

The popularity of the fictional holiday has led to celebrations around the world. In 2005, the Wagner Companies in Milwaukee manufactured aluminum rods and provided one to then-Wisconsin Gov. Jim Doyle, which he displayed in the Executive Residence, according to the Wisconsin Historical Society.

Wisconsin-based “Animal House” actor Mark Metcalf, who played the maestro on “Seinfeld,” displayed his Wagner-made Festivus poles at his restaurant, the historical society noted.

On December 6, 2010, former U.S. Rep. Eric Cantor, R-Va., hosted a Festivus-themed fundraiser in Washington, D.C., Politico reported.

From Florida to Australia, made-up holidays kept popping up.

In 2022, even the official “Seinfeld” social media accounts helped boost Festivus’ popularity by sharing a link on change.org advocating for making Festivus a national holiday.

According to the run’s organizers on Facebook, the 13th annual Festivus 5K Run for Autism took place on December 15 in Salem. Cindy and Rick Johnson founded the race after their son joined the Northshore Education Consortium as a seventh-grader.

“Our son was diagnosed with the spectrum when he was about five years old, and like most parents whose child has a health issue, we looked for ways to help others by giving back to the community,” said Cindy Johnson in 2023 to MassLive. “So we started this road race, we are both runners and this is our passion.”

The run raises money for children with autism at the Northshore Education Consortium, of which Cindy Johnson is founder and president.

The Johnsons are big “Seinfeld” fans themselves and thought an “anti-holiday run” in the spirit of Frank Costanza’s anti-consumerism that fueled Festivus would add to the fun.

“Sometimes the holidays aren’t exactly what you want, and that’s a festivus for the rest of us, as they say,” she previously said.