The real father of Festivus: Before Frank Costanza there was Daniel O'Keefe, who created the beloved 'Seinfeld' holiday

Yes, Christmas Day is almost at hand. Which means so is Festivus, that December 23 holiday most of us were introduced to via the now-classic 1997 episode of "Seinfeld" (an episode called "The Strike").

But for "Seinfeld" writer Dan O'Keefe and his brothers Larry and Mark, Festivus was a real childhood celebration, invented by their father, Daniel L. O'Keefe, in honor of his first date with his eventual wife of 48 years, Deborah.

Dan Sr., a Reader's Digest editor who worked with Ray Bradbury, spoke 40 languages, and was portrayed in a WB sitcom by "Beverly Hills Cop" actor (and onetime "Seinfeld" guest star) Judge Reinhold, passed away at age 84 in August.

In his honor, Yahoo! TV spoke with Dan O'Keefe Jr. about his father, the father of Festivus, and below are eight things you never knew about the beloved TV and real-life holiday:

1. Frank Costanza (Jerry Stiller) invented his Festivus as a "holiday for the rest of us," an alternative to the overcommercialization of Christmas, but the O'Keefe family celebrated Festivus in addition to Christmas. "A big misperception is that, 'Oh, you guys didn't celebrate Christmas.' In the show, that's the case, because those are characters who are rather dysfunctional, the Costanza family. In our family, though they were certainly dysfunctional, we celebrated Christmas, and this was just an additional layer of weirdness," O'Keefe says.

Watch the story of Festivus on "Seinfeld": 

2. In "The Strike," the Costanzas celebrate Festivus on Dec. 23. The Real Festivus -- "'Festivus Classic' versus 'New Festivus,'" Dan O'Keefe jokes -- would take place any time of year. One year, there were two Festivus occasions. "We sort of arbitrarily assigned it to December 23 on the show, but in reality, it floated. It sort of happened whenever my dad felt it coming on. Maybe one day we'd come home from school and there would be candles lit … we got very little warning. It would just be happening. The decorations would be up, the music would be playing, and he would be coming toward us with a tape recorder in his hand. And there would be strange joke presents and an even stranger dinner, and then we'd go upstairs and talk into the tape recorder for several hours. Lots of food and drink and general carousing and peculiarity."

3. There were no feats of strength, wrestling, or aluminum pole in Festivus Classic, but there were the tape recordings. As Dan O'Keefe writes in his book "The Real Festivus," another inspiration for the holiday was his father's love of the Samuel Beckett play "Krapp's Last Tape," in which a man makes audiotapes and listens to ones he's already recorded. O'Keefe Sr. had lent the play to his wife on their first date, and, using an "ancient" tape recorder he'd been given at work, he began recording the family's themed Festivus celebrations. "The Real Festivus" includes transcripts of Festivus recordings from 1976 (theme: "Are we scared? Yes!"), 1977 ("Are we depressed? Yes!"), 1980 ("Too easily made glad?"), and 1985 (a nonthemed year).

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4. There was also a clock and a bag at every Festivus celebration, and O'Keefe says he could never get a straight answer out of either of his parents about the meaning behind the odd pairing. "One year my dad dramatically nailed it to the wall, and the nail remained, and then on future Festivii, he just hung it back on the same nail. But the symbolism … those were the real symbols (of the holiday). Something to do with my family and my father and mother's first date … I don't know. It was a little duffel bag and an old-fashioned alarm clock, and the bag hung on the wall, but the clock was made to peek out of the bag so you could see there was a clock in there. And I still don't know what it means! No one ever told me, and every time I would ask, they would say, 'That's not for you to know!' well into my 30s."

5. Festivus Classic also included funny hats fashioned from materials like paper and Play-Doh, Play-Doh sculpture contests at the dinner table, anti-fascism signs, gift-wrapped rocks and rolls of toilet paper, and musical selections that ranged from opera and '60s French pop star Sylvie Vartan to recordings of the O'Keefe boys at school pageants and something Dan O'Keefe describes as sounding like an Italian version of Alvin and the Chipmunks. Though none of those real-life details made it into the TV version of the holiday, O'Keefe says his dad loved that his creation has become a pop culture phenomenon. "He liked the sheer pride of ownership. And he liked the way it had been reinterpreted," says O'Keefe, who was also a writer on "Married … with Children" and "The Drew Carey Show." "At one point he said we didn't have any wrestling, at least not officially, and no pole, but those would have been welcome. If he had thought of them, he might well have done that. He also just liked the fact that, in a small way, anyone who was celebrating Festivus was also celebrating our family."

6. The O'Keefes, who celebrated Festivus from 1966 through 1990, were celebrated not only in the "Seinfeld" episode written by Dan but also in a short-lived WB sitcom created by Mark O'Keefe. "The O'Keefes," which aired for five episodes in 2003, starred Judge Reinhold as the father, "Psych" star Kirsten Nelson as his wife, and "Lincoln" and "Running With Scissors" star Joseph Cross as Danny O'Keefe.

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7. The last O'Keefe family Festivus celebration was a stealth operation. "We had finally said, 'This is insanity; we'd rather not celebrate it anymore,' and my dad said, 'Oh, OK, sure,' Dan O'Keefe says. "And we noticed there were some things on the wall -- my brothers and I were home for break from college -- and we said, 'Are those Festivus decorations?' And we were like, 'No, no,' but then my dad kept sidling up to us and asking us questions about how the year had gone for us, in a very stagey manner. And he was wearing four layers of overcoats inside the house, with the heat on, and eventually we realized he was following us around the house, tape-recording our responses and then whispering into his coat to (add) his thoughts. (Laughing) When he started asking us to sing for no apparent reason in the middle of the day, we figured it out, and we said, 'Are you secretly having a Festivus without telling us?' That was the last one we celebrated, in 1990."

8. But Festivus may live on, and not just on "Seinfeld" and in the homes of fans who've purchased Festivus Poles (https://www.festivuspoles.com/pages/Festivuspoles.htm) for their own celebrations; Festivus Classic may make a revival in the O'Keefe family. "My wife and I are still debating whether or not we want to actually celebrate it," O'Keefe says.

"It's always difficult to decide: how to talk to your children about Festivus? There are no real pamphlets available," he jokes. "But there really should be some kind of outreach available, because you don't want kids picking it up on the street."

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Self-taught linguist Dan Sr. and his English professor and author wife Deborah O'Keefe inspired all three sons to pursue successful entertainment careers, from Dan's work as a writer on "Seinfeld" and "The League" to Mark's work as a writer and producer on "Bruce Almighty" and Larry's composing work for "Bat Boy: The Musical" and the Tony-nominated "Legally Blonde" musical. What does Dan O'Keefe want people to know about his dad, the larger-than-life creator of Festivus?

"That while an actual genius, he thought the movie 'Howard the Duck' was one of the finest pieces of cinema ever produced in America, and I'm not kidding," O'Keefe says. "That he was the funniest and smartest guy I ever met … that, at one point, he lost 50 pounds by switching to light beer … that he and my mom were married for almost 50 years, which he was quite proud of … that well into his 80s, even if he wasn't leaving the house, he would wear a suit and tie, because that's what he did in his generation … that he was always terribly ashamed that, even though he volunteered twice for service in World War II, he 4F'ed because he had terrible eyes and was a little too young, and he always felt bad about that because he was 16, 17 on the homefront when all the adult males were off fighting … that he was a lifelong Democrat and was thrilled by the election of our president, and that he was a good guy."