Here is the Encyclopedia Dramatica hypothesis:
God is the Santa Claus for adults. He is the protagonist of the Bible, a book which has somehow sold moar copies than Harry Potter, making it the most successful work of fiction evar. The Bible, the chronology of God's Adventures, is a volume of pornography, rape, incest, and other sorts of epic win. It is believed that God created the universe with no other reason than to play a game of The Sims against Satan.