Plasma glass is fun to experiment with for those of you with a Tesla coil. This Neon Glass Plasma Lamp is also worth a look. It can be used as a regular mug but lights up when you install it on the stand. It works on USB and battery, so no need to buy a Tesla coil.
This handmade plasma glass lamp measures 15cm high and 10cm deep. The bad news? It doesn’t come cheap.