Good Riddles

Question: What's the only school where you have to drop out to graduate?

Question: What is at the end of everything?

Question: what is yours but you can't actually hold ?

Question: I'm a measurement of time.
But you'll find me on a map, not a clock.

What am I?

Question: A lawyer has a brother who is a Catholic priest. The lawyer wants to be a priest as well but cannot. Why not?