Julie Louis-Dreyfus did not appear in the pilot episode of Seinfeld

Contrary to pop culture lore, the fake holiday "Festivus" was not created by Seinfeld writers. It was conceived in a 1966 issue of Reader's Digest

In the first episode of Seinfeld, Kramer's last name was Kessler. Producers were concerned that Larry David's friend Kenny Kramer (who was the bases for the character) would object to the use of his name. Eventually they worked out a deal and the character was renamed "Kramer"

Jerry Seinfeld's former friend Michael Constanza sued the "Seinfeld" creators, claiming that the character of George was based on him and thus violated his privacy. He lost

In every episode of Seinfeld, there is either a visual reference or a mention of Superman

Larry David provided the voice of the George Steinbrenner character in "Seinfeld"