See this song:
THE BALLAD OF LADY MONDEGREEN
…and these related threads:
Mistakes I Have Made When Listening To Songs
There's a Bathroom on the Right
Misspoken, misheard, but accepted
Misheard words
Mis-heard session tune titles
…and these related web sites:
The Ants Are My Friends
Funny Misheard Lyrics
The Humorous Compendium of Misheard Lyrics
Brain Candy Poetry & Song Collection/Mondegreens
KissThisGuy