I have one more Beatles tidbit for you, taken from the book Revolution in the Head, as have been the Beatles items of the past few days. The book, to tell the truth, is a bit disappointing; it purports to be a musicological look at each recorded Beatles number but ends up spending half its time telling the stories behind the songs and, in the end, isn't really satisfactory on either end.
It does have a neat Beatles timeline, though, which informs us that on November 9, 1966, Paul McCartney crashed his moped while out riding with his buddy Tara Browne. A rumor sprang up that Paul had been decapitated, leading to his being Officially Pronounced Dead. (Browne too would go down for the count just over a month later.)
Shortly thereafter Faul - the False Paul - was enticed to join the Beatles. The other Beatles would have gotten away with the whole thing had they not felt the need to taunt the newbie, making Faul wear a black carnation during the shooting of Magical Mystery Tour and whatnot, just to remind him that he wasn't a real Beatle.
Anyway, it was on that very same day, November 9, 1966, that John Lennon met Yoko Ono at her art exhibit in London. So if you're looking for the day that was the beginning of the end for the Beatles, that would be it.