None. They already glow.
Two, but you have to get them in the lightbulb first.
A: So who wants to know Why do *you* want to know Are you a cop
A: WHAT
Who wants to know? .... saw this joke in today's
I came from Chernobyl, I had a tail!
Chernobyl fallout
Got to glow now !
None. People that glow in the dark don't need lights.