To log on.
or
Drinking, bathing, washing, swimming, etc.
or
That's proprietary information. The answer is available from AT&T on payment of license fee (binary only).
or
Super Pickle!
or
None, because people who glow in the dark don't need light bulbs.
Note: Topical to the Chernobyl Reactor disaster of 1984.
or
he said "Not you again".
or