Answer:
What moves and touches water but doesn't get wet?
How do you discover something that does not exist?
How can you throw a ball 20 meters, and have it come back to you without hitting anything?
A train just leaves a station and enters a tunnel. Where is the best place for a claustrophobic person to sit?
I have two coins, one is marked George I and one is marked George IV. One is genuine but one is a forgery. Which is the forgery?
As round as an apple. As deep as a cup. All the king's horses can't pull it up.