You're travelling to some village. At some point there is a fork in the road. You could go two ways but only one of them leads to the village. Lucky for you there are two men standing next to the fork. But unfortunately one of them always lies and one always speaks the truth and you do not know who is who. Since the men do not really like to help you, you are allowed to ask one of them only one question. Which question should you ask?

Ask one of the men, "if I would ask the man standing next to you: which is the road to the village?, what would he answer?"
If you ask this to the liar, he will point you in the wrong way.
If you ask this to the one who speaks the truth, he will also point you in the wrong way.

So after asking the question, take the other way. This will bring you in the village.