Riddle: You're trying to get to truthville where everyone tells the truth. So you're driving along and you come to a fork in the road. You know that one road leads to truthville and the other to lieville, where everyone tells lies.So you have no idea where to go when you see a girl right in front of the fork in the road. You figure, she must be from lieville or truthville. What question do you ask the girl to get to truthville?
Answer: You ask her to point to her hometown. If she's from lieville, she'll lie and point to truthville. If she's from truthville, she tell the truth and point to truthville. Either way, you get to truthville.