The correct answer to the classic trick question “Have you stopped beating your wife yet?”. Assuming that you have no wife or you have never beaten your wife, the answer “yes” is wrong because it implies that you used to beat your wife and then stopped, but “no” is worse because it suggests that you have one and are still beating her. According to various Discordians and Douglas Hofstadter the correct answer is usually “mu”, a Japanese word alleged to mean “Your question cannot be answered because it depends on incorrect assumptions

The word “mu” (via. Edward O’Connor) Via: catb.org.