1- Elaine was not an original part of the cast When Seinfeld premiered on July 5, 1989, it actually aired under the name The Seinfeld Chronicles. The layout and pacing of the show were essentially the same, with one notable (and unmistakable) difference: the absence of Julia Louis-Dreyfus’ Elaine Benes. Character actress Lee Garlington was originally cast as a sassy waitress named Claire, and -- given that she was credited as a series regular in that pilot episode -- there’s little doubt that her character was meant to fill the void that Elaine eventually came to fill. It’s also interesting to note that Claire worked at an establishment called Pete’s Luncheonette, rather than at the infamous diner (Monk’s Cafe) that eventually came to define the series. And although Claire certainly filled the same purpose as Elaine -- i.e. she would call Jerry and George on their misguided male ideas -- the character was unceremoniously dropped once Seinfeld premiered almost a year later. Julia Louis-Dreyfus, an SNL veteran with an extensive background in comedy, ultimately won the newly created role of Elaine Benes, beating out such familiar faces as Patricia Heaton, Rosie O’Donnell and Megan Mullally for the part. 2- Other actors originally played Newman, Morty Seinfeld and Frank Costanza Though Jerry Stiller has become inexorably connected with his Seinfeld alter ego, Frank Costanza, it’s interesting to note that he wasn’t the first actor to play the character. George’s cranky father was introduced during season four in the episode “The Handicap Spot,” which follows the younger Costanza as he publicly embarrasses his dad after parking in a handicap spot. The original episode starred veteran actor John Randolph as Frank, but judging from the palpable chemistry between Stiller and television son Jason Alexander it’s not surprising that Randolph was let go and Stiller was hired. In an effort to maintain continuity within the series, Seinfeld’s producers reshot all of Frank’s scenes in “The Handicap Spot” with Stiller (the original Randolph footage hasn’t been seen since the original airing). That wasn’t the only time a role was recast in midstream: Jerry’s father, Morty, was first played by actor Philip Bruns in the episode “The Stakeout,” but was eventually replaced by the late Barney Martin. Additionally, Newman -- so memorably played by Wayne Knight -- was introduced in the episode “The Revenge” as just a voice that the series co-creator, Larry David, provided. When the decision was made to turn Newman into a recurring character, Knight was hired and asked to dub over David’s work in that episode. 3- Jerry, George and Elaine’s siblings were never seen Throughout Seinfeld’s nine-year run, viewers were introduced to several of the four central characters’ relatives; in addition to Jerry’s and George’s parents, we also met Kramer’s mother, Babs, and Elaine’s father, Alton. Yet, even the most astute Seinfeld fan may not realize that George, Jerry and Elaine all have siblings who were mentioned but never actually seen. In the series’ infamous “Chinese Restaurant” episode, Jerry makes an all-too-brief reference to a sister who’s never mentioned again during the show’s run (we don’t even learn her name). George’s brother fares slightly better in that he’s actually mentioned twice: in “The Suicide” and “The Parking Space” episodes. Finally, there’s Elaine’s sister Gail -- whose son memorably hid the nipple-baring Christmas card Elaine accidentally sent out to a myriad of friends, coworkers and relatives in the episode “The Pick.” 4- Festivus was created in 1966 by a Reader's Digest editor It’s clear that Seinfeld has been responsible for several indelible additions to the pop-culture pantheon, yet there’s little doubt that the phony holiday of Festivus stands above the rest. In the ninth-season episode “The Strike,” Frank Costanza boasts about creating Festivus during George’s childhood out of frustration with the various rituals associated with Christmas. Rather than emphasize good will and togetherness, Festivus asks those who partake in its festivities to participate in confrontational exercises, such as the “Feats of Strength” and the “Airing of Grievances.” Yet, what most Seinfeld fans don’t realize is that Festivus was actually created before Jerry Seinfeld even hit his teen years. Back in 1966, Reader’s Digest editor Dan O’Keefe invented Festivus as a means of celebrating the first date he ever had with his wife. Though the first Festivus transpired during the month of February, the faux holiday was eventually moved to December. Festivus came to Seinfeld in the form of O’Keefe’s son Daniel, who was working for the show as a writer and decided to include the holiday in the aforementioned episode “The Strike” (he added in the now-infamous aluminum pole). 5- The series began and ended with a conversation about a shirt button When the end inevitably came for Seinfeld, the shows' many fans began speculating how the series might end. Would Jerry and Elaine finally acknowledge their feelings for each other and get married? Would George find a job he could actually hold onto? Would Kramer stop bursting into Jerry’s apartment unannounced? As it turned out, the series finale -- penned by co-creator Larry David -- ultimately sent the cynical foursome to prison for their lack of compassion toward others and the show concluded with the gang settling not-so-comfortably into their new lives as inmates. Prior to the final scene in which Jerry can be seen performing a stand-up routine for his fellow prisoners, Jerry and George participate in a discussion revolving around the placement of a button on George’s shirt. This conversation is almost a word-for-word reproduction of the dialogue that opened the series way back in July 1989, as the two friends sat in Pete’s Luncheonette and debated the merits of George’s button placement. It proved to be a simple yet wholly effective way of demonstrating that even though they may be on their way to prison, Jerry and the gang’s flippant, thoroughly detached sensibilities will remain intact no matter where they wind up.