Related:

• How many theoretical physicists -- does it take to change a light bulb?
  If you know how many, you can't know if they've done it yet....
• How many witches -- does it take to change a light bulb?
  It depends on what you want them to change it into....
• How many Scorpios -- does it take to change a light bulb?
  Why do you want to know? Are you a cop?...
• How many theoretical physicists -- does it take to change a light bulb?
  The probability that the light bulb will actually be changed in any time interval is independent of how long you've been waiting....
• How many Romanians -- does it take to change a light bulb?
  How many packs of cigarettes are you willing to give them?...
• How many lawyers -- does it take to change a light bulb? How many can you afford?
• How many Unix hacks -- does it take to change a light bulb?
  As many as you want; they're all virtual, anyway....
• How many magicians -- does it take to change a light bulb?
  Depends on what you want to change it into....
• How many aerospace engineers -- does it take to change a light bulb?
  None. It doesn't take a rocket scientist, you know....