Reader [Xellers] sent in his newest instructable: DIY Electron Accelerator: A Cathode Ray Tube in a Wine Bottle. While not exactly what you might think of a cathode ray tube, the basics are in place. A wine bottle is used as a vacuum chamber and a 9kv neon transformer is attached to a stopped in the top. A cathode is placed mid way, the air is sucked out with a pump, and high voltage is applied.
Naturally as more air gets pumped out the electric arc intensifies into a pretty solid plasma filling the space between the two contacts. While mixing drilled glass with a vacuum and high voltage sounds like an awesome hospital story [Xellers] does cover some safety points including the possibility of this thing putting out some nasty waves.
One thing that is not mentioned (that I saw) is this is very similar to how florescent light tubes work and without florescent material lining the chamber it will spit out quite a bit of UV light (notice germicidal UV lights are clear). So you will want to watch your eyes!
Join us after the break for a quick video.