Before Columbus' discovery....

Before Columbus' discovery why did mankind think the Earth was flat?

http://www.basicjokes.com/djoke.php?id=2427

Why do croutons come in airtight...

Why do croutons come in airtight packages? Aren`t they just stale bread to begin with?

http://www.jokes-db.com/jokes/deep-thoughts-jokes

Why is the man who invests ...

Why is the man who invests all your money called a broker?

http://www.jokes-db.com/jokes/deep-thoughts-jokes

When someone asks you...

When someone asks you, "A penny for your thoughts" and you put your two cents in . . . what happens to the other penny?

http://www.jokes-db.com/jokes/deep-thoughts-jokes

If love is blind...

If love is blind, why is lingerie so popular?

It's always darkest ...

It's always darkest just before dawn.  So if you're going to steal the neighbor's  newspaper, that's the time to do it.

http://www.joecasaletto.com/jokes/deep.htm 

Do infants enjoy...

Do infants enjoy infancy as much as adults enjoy adultery?

http://www.jokes-db.com/jokes/deep-thoughts-jokes