Just about every operating room like the one I work in has an electrical cutting and cautery device. They’re often generically called Bovies, although many companies other than Bovie make them now. They work as an electric scalpel, and also coagulate small blood vessels to stop bleeding. Two different types of electrical current are used, and the machine makes a different tone so the surgeon can audibly verify which current is being used.
Usually, these currents get used sort of randomly but yesterday one surgeon was alternating back and forth between the two pretty steadily. Something in the sound caught my attention and all of a sudden it came to me…Purple Haze by Jimi Hendrix. Those spooky, evocative opening notes form an interval called a tritone, or Diabolus in Musica (Devil in Music). Check out this Wiki entry for the interesting story:
http://en.wikipedia.org/wiki/Tritone
I think these two tones are also used in emergency sirens for their attention grabbing qualities on the human ear.
Check out my long-time signature, Paul. 
I noticed that a long time ago and figured you’d chime in here.
Fascinating concept isn’t it?
Speak of the Devil, and he appears.
I thought for sure you were working up
to an Alternating Current joke there.
No, he was trying to be more direct.
His jokes are usually not current. 
Huh? Watt?
Just remember that Ohm’s law is invalid because resistance is futile.
You the Joule in our crown.
No Ohms, Watts or Joules here, but afraid I keep reading the thread title as the Devil in Oregon!
Edited the original title. The way it was, it sounded like a review of a heavy metal concert in Portland.