Good Riddles

Question: You find me behind the stars; or in a sixth, seventh, or third.
It takes something round, a computer, and me to make pie.
I am bigger than anything you can think of.

What am I?

Question: What has thousands of ears but can't hear a thing?

Question: A man was born on January 1st, 23 B.C. and died January 2nd, 23 A.D. How old did he live to be?

Question: This sentence is false.

Is the preceding sentence true or false?

Question: Having some, you want more. But when you have too much of it you feel bored. Everyone people wants it, and some have to much of it. What is it?