Philosopher Watch Solution
One absentminded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he traveled on foot to his friend's place few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock. How did he know?
Clocks can measure time even when they do not show the right time. You just have to wind the clock up and...
We have to suppose that the journey to the friend and back lasts exactly the same time and the friend has a clock (showing the correct time) - it would be too easy if mentioned in the riddle.
Now there is no problem to figure out the solution, is there?