There is a huge number puzzles that are similar to this one. You can try "the hardest logic puzzle ever" if this one is too easy.
You are travelling to KnightTown where all residents are Knights and always tell the truth. You reach a fork in the road. One path leads to KnightTown and the other to KnaveTown, where all residents are Knaves who always lie. You do not know which road leads to which town. You encounter a person at the fork, who is either a Knight or a Knave. You are allowed to ask only one question to the person standing at the fork. What question can you ask to find the right road, not mattering whether the person is a knight or a knave?