I don't know. What's a gaffer with you?
(Laughs uncontrollably for ten minutes. Looks back at post; considers cutting 'uncontrollably' because it's a ridiculous adverb. Moves on.)
A gaffer is the head or chief electrician on a film set. Sometimes there's a 'head gaffer' which just means the head head gaffer.
(Proud of himself. Wonders if he shouldn't go to the same parenthetical well a second time. Moves on.)
You could've gotten this information through googler or googly or whatever that thing's called. I guess you came here because you wanted a funny answer.
(Considers whether or not the parenthetical approach is humorous enough. Decides it isn't.)
How 'bout this? A gaffer is someone hired to fuck things up, to make others look good. The most famous example of gaffers are the people on infomercials who can't cut a tomato without painting the walls with their inadequacy. So, on a film set, the head gaffer is the best guy at acting poorly, therefore making the on-screen talent feel confident.
Director: "Hey! Eddie Jim? Get in here and do a take."
Eddie Jim: (Imma gaff the shit out of this.) "Okay. Four score and sevens poops ago!"
Director. "Just terrible. Thanks, EJ. Okay, Ashton Kutcher, time for you to give it a go."
Ashton Kutcher: "Wait. In this example, am I also a gaffer?"
Director: "What example? What do you mean? We're wasting daylight, Kutcher, let's do this."
Ashton Kutcher: "Are you not aware that this is all a fabrication? It's just an example on a dude's blog."
Director: "Even if that's the case, why would you think you're also a gaffer?"
Ashton Kutcher: "Because I'm a terrible actor."
Director: "True. But you got Mila Kunis pregnant. So you're a success in all things."
Ashton Kutcher: "That's true."
Short Answer: If even one person out there is now confused about what a gaffer is, I've done my job.
Note: Did you know that Ashton Kutcher spends much of his time as an activist, trying to put a stop to sex slavery? Yea, that's not relevant to anything here, and it isn't a joke, but still. Nice work, Kutch.