After you die, you somehow appear in a mystical room, which has two doors in it. In front of each door there is a keeper - one of them always lying, the other one always telling the truth. If you enter the door of the lying keeper, you go straight to Hell. If you enter the door of the truthful keeper, you go straight to Heaven. You can ask one of the keepers whatever question you want (you don't know which keeper is lying and which is truthful). What should you ask in order to go to Heaven?
You can point your finger to one of the two rooms and ask any of the keepers the question "If I ask the other keeper whether this room leads to Heaven, would he say YES?". If the answer is NO, go through that door, if the answer is YES, go through the other one.