I've been thinking a lot about the number “a billion” recently. Someone once blogged an interesting tidbit about it:

A billion seconds ago it was 1959.
A billion minutes ago Jesus was alive.
A billion hours ago our ancestors were living in the Stone Age.
A billion days ago no-one walked on two feet on earth.

How much is the U.S. government spending in Iraq every month? Ten Billion Dollars. Monthly.