1) Something that pertains to a joke, and a pretty damn big one. It can be used in one sentence to indicate a proper joke was just spoken.
2) It can also be used to counteract a joke, or otherwise stating the joke was a fail.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

The woman, for once, gets a chance to vote on which sexual position to do in the bedroom.