While looking into more information about Larry David's vocal impression of George Steinbrenner on 'Seinfeld', I found this item at WikiSein:
In one episode, "The Wink", Steinbrenner mentions all of the people he fired, with him saying Billy Martin four times. He also mentions then-current manager Buck Showalter, then quickly clams up about it.
Though the show meant it as a joke, it turned out to be prophetic: just weeks after the episode aired, the real life Steinbrenner did not bring back Showalter as Yankees manager and replaced him with Joe Torre.
It wasn't the first time that Toobworld proved to be prophetic. The most famous example might be found in the 'Star Trek' episode of "Tomorrow Is Yesterday". Uhura tunes into a radio news summary which reports that the first manned Moon shot from Cape Kennedy with three astronauts is scheduled for Wednesday - the real Apollo 11 carrying three astronauts was launched from Cape Kennedy on 16 July 1969, a Wednesday.
At the time this episode aired, some conservative estimates by NASA held that it would be well after 1970 before man landed on the moon.
Sadly, on the day after this episode was aired, Gus Grissom, Ed White, and Roger Chaffee tragically lost their lives in the Apollo 1 capsule.