A logician saves the life of a tiny space alien. The alien is very grateful and, since she’s omniscient, offers the following reward: she offers to answer any question the logician might pose. Without too much thought (after all, he’s a logician), he asks: “What is the best question to ask and what is the correct answer to that question?” The tiny alien pauses. Finally she replies, “The best question is the one you just asked; and the correct answer is the one I gave.”

Joke by Rich Hilliard and found at Self-reference jokes: A collection