My memory is that the two most covered songs ever are:
Yesterday (Lennon & McCartney)
Summertime (George Gershwin)
Yesterday is the most covered song (over 3,000 covers?), but Summertime has by the more interesting covers. It's a kind of part time hobby of mine to collect Summertime covers (if only in my mind
). Some of my favourites are:
Louis Armstrong & Ella Fitzgerald
Janis Joplin
Sam Cooke
There's also an instrumental version by John Coltrane which I haven't got to hear yet, plus about 3,000 others.
There's also an interesting song by Eminem called Rock Bottom, which, although not a cover of Summertime, alludes to the song by referencing the unmistakable guitar riff from Janis Joplin's cover.
'I can't even fit all my wife's clothes into a suitcase for travelling. So you want me to believe we're going to put all of the planets and stars and everything into a sandwich bag?' - q3psycho on the Big Bang