On the Upper West Side lived a man who was a very militant atheist but he sent his son to Trinity School because, despite its Christian roots, it was a great school.  After a month, the boy comes home and says casually, "By the way Dad, do you know what Trinity means?  It means the Father, the Son, and the Holy Ghost."

The father can barely control his rage.  He seizes his son by the shoulders and declares, "Danny, I'm going to tell you something now and I want you never to forget it.  There is only one God and we don't believe in Him!"