Answer:
Two fathers and two sons are in a car, yet there are only three people in the car. How is this possible?
What is as big as you are and yet does not weigh anything?
An archaeologist unearths a coin bearing the inscription "57BC". How does he instantly know that it's a forgery?
Twelve pears hanging high, twelve men passing by. Each took a pear and left eleven hanging there. How can this be?
How do you make the number one disappear by adding to it?
Iβm grown from darkness but shine with a pale light. Very round I am and always a lady's delight.