“The Hobbit: An Unexpected Journey” director Peter Jackson and editor Greg Daniels sit in an editing booth.

JACKSON: Well that’s great! It communicates the epic scope of the book, assures the audience there’s plenty to cover here, gets them excited for new worlds unexplored. Now we just need to add a fart joke.

DANIELS: …Sorry?

JACKSON: A fart joke! You gotta end a trailer with a fart joke. That’s how people know the movie’s not all serious.

DANIELS: But… we don’t have a fart joke in this movie. That would be horribly out of line with the film’s tone.

JACKSON: Damn. Well what do we have?

DANIELS: How about a “well that could’ve been worse” gag?

JACKSON: Does something huge land on everyone and go “boooossshhhhh” and inexplicably not injure anyone, making the whole thing look like a Looney Tunes reboot?

DANIELS: Apparently, yes.

JACKSON: I can settle for that.

http://www.youtube.com/watch?v=yYz0JWJioOM