One; after reflecting in the twilight on the merit of the previous bulb.
or
Only one, but she/he'll have to go out and buy the light bulb adaptor card first, which is extra.
or
Three skunks fighting over a pickle
First dog: My master calls me Furball. How about you?
Second Dog: My master calls me Sitboy
or
He was tired of working for peanuts.
or
A porcupine with split ends
or