It's something I could really see myself doing.
or
None, because they were copycats
or
None, because people who glow in the dark don't need light bulbs.
Note: Topical to the Chernobyl Reactor disaster of 1984.
or
The bartender offers him a warm smile and says, "For you, no charge".
or
They're both plastic and little boys turn them on.
or