Then prop the CD up on top of your tesla coil. (Careful it's hot!) Position a grounded electrode of some kind above it so that the sparks get concentrated into the CD. (I used an aluminium rod that was lying about.) Now stand well back and activate the Tesla coil.
The whole CD lights up with bright blue sparks! It's an awesome light show. It didn't last for long, though: the metal coating got blown off the CD. Tiny flakes of it went everywhere.
Since we had an old microwave handy, we tried microwaving a lit candle in the hope of creating ball lightning. Nothing happened, so we tried zapping the candle with the Tesla coil instead.
The sparks were drawn into the column of hot air from the flame, creating a neat ray gun effect. But still no ball lightning.