Riddle: You have been held prisoner for something you didn't do for 10 years. You eentually manage to convince them to let you go, but there is one last thing you must do to gain freedom. The guard brings you to a room which has 2 doors at the other end each of which is guarded by a man. He says to you, "one of these doors leads to eternal freedom and happiness, the other leads to hell. You are allowed to as 1 question to one of the men. 1 of these men ALWAYS tells the truth, the other ALWAYS tells a lie." Which one question do you ask?
Answer: you ask either of the men, "which door would the other man point to if I was to ask him which door is the way to freedom?" This way they will both point to the same door (the door to hell) and you walk through the other door.