WFMU's blog archive has a wonderful posting titled "Stairways to Heaven, Stairways to Hell," linking to 101 versions of "Stairway to Heaven" (Zeppelin's, not Sedaka's):
Here are 101 versions of the song that doesn't remain the same, depending on whether it's the Australian music hall version, the Gilligan's Island version, the backwards version, the backwards splice-and-dice quarter note version, the glass harmonica version, the Doors version, the reggae version and on and on (all MP3s).
Some are good; many are so bad, they're great.
I first saw (and heard) this last year, but I didn't have a blog then, so here it is.