I happened across a screendump of a 4Chan thread today that had lolcat pictures that matched up with the lyrics of Enter Sandman. Someone posted a comment saying that they’d love to see it with the soundtrack. So, I fired up iMovie and bingo: Lolcat Sandman.
Of course, the music copyright is owned by Metallica, but I actually had to go and buy it from iTunes because I’d deleted my “unofficially obtained” copy a while back.
UPDATE
Oh well, it was fun while it lasted. I got a takedown notice from Warner Music Group, via YouTube. I used the YouTube tools to remove the soundtrack. Sorry.