Since nobody has shared something yet, I'll go first:
This is an iconic piece of music used in a lot of cartoons and movies. What makes it obscure is that nobody knew what the name was, so most people probably know it as "spooky background music" or "bad guy does something kinda evil - the song" or something.
I remember a website called Y8.com
It was a website that was for playing flash games from other creators. It's now littered with crappy flash games equivalent to one found on such websites as "Cute-zee.com" or other similar ones. It's still around today, but it's just crap now.
If you want to play flash games now, Newgrounds is actually better, since it has more quality control, sort of.