For some, the most important holiday in December falls on the 23rd. That's the day to celebrate Festivus, the made-up holiday from an episode of Seinfeld, which has since taken on a life of its own.

What Is Festivus?

In the 1997 Seinfeld episode "The Strike," Frank Costanza (Jerry Stiller) explains the tradition of Festivus, which he's invented as an alternative to Christmas, calling it "a Festivus for the rest of us." It's a strange, off-putting celebration that's perfect for the volatile Frank to unleash on his neurotic son George (Jason Alexander).

Festivus was inspired by a similar holiday invented by author Daniel O'Keefe, father of Dan O'Keefe, a Seinfeld writer and story editor who co-wrote "The Strike." Dan O'Keefe took elements from his family's unique traditions and combined them with ideas from other Seinfeld writers.

How to Celebrate Festivus

As explained by Frank Costanza in "The Strike," there are three key elements to a Festivus celebration, always held on December 23. It starts with the Festivus pole, an unadorned aluminum pole that is the holiday's version of a Christmas tree. "It requires no decoration. I find tinsel distracting," Frank Costanza says of the stark holiday accessory.

At Festivus dinner, families participate in the "airing of grievances," sharing how they've been disappointed by each other in the preceding year. After that come the "feats of strength," wrestling-style showdowns that proved uncomfortable and humiliating for poor George Costanza as a child.

Anyone who isn't a sitcom character might want to make their airing of grievances and feats of strength a little less intense and vindictive, although Frank Costanza probably wouldn't approve.

Learn More About Festivus

In the years since "The Strike" aired, real-life Festivus celebrations have become so popular that there have been multiple books written about the holiday, including Allen Salkin's Festivus: The Holiday for the Rest of Us and Mark R. Nelson's Festivus The Book: A Complete Guide to the Holiday for the Rest of Us. Dan O'Keefe himself wrote about his family's traditions in his book The Real Festivus: The True Story Behind America's Favorite Made-up Holiday.

Of course, the best place to learn about Festivus is at the source. All nine seasons and 180 episodes of Seinfeld are streaming on Netflix ($8.99+ per month), and "The Strike," which is the 10th episode of the final season, is a series highlight.