I bought a couple of plasma flashers when the prices dropped. The high frequency high voltage source easily ionizes the low pressure gas inside the glass sphere. A florescent bulb held near the flasher will light between your hand and the end closest to the flasher. Yes, you are part of the circuit (very low current, fortunately).
I like to tell the story about my son, who was asked by his middle school science teacher to weigh light. Holding one end of a florescent bulb in one hand and the other end near a hidden plasma flasher, I say, “Here I have a lit florescent bulb that is not plugged in. You should weigh it with the light inside.” Then I touch the bulb with my other hand and sweep that hand down towards the plasma flasher saying, “Then just squeeze the light out of the bulb and weigh it again.”