The music turned out AWESOME.
In Call of Cthulhu, I love throwing cheap shots at my players. One of the ways they've known bad crap will happen is that they hear, somewhere in their heads, insane piping.
This was the campaign send-off, and I wanted to give them something to remember.
I prepared the mp3 as above then prefaced it with 3 minutes of silence. Right when the tension was getting high - when they were in a place they definitely didn't want to be in - I ran off to the computer in my room, cranked the volume, and pushed play. I killed some time spooking them out and when I heard it, I had their tour guide (long story) say, "Wait... Listen... there it is now..."
One of the girls almost lost bladder control and my other players just freaked out a bit. It was worth every minute spent preparing it.
-O