Apparently he is a massive God of War Fan. :D
http://www.shacknews.com/article/102581/elon-musk-accidentally-tweets-phone-number-to-john-carmack-has-god-of-war-voicemail-message
http://www.shacknews.com/article/102581/elon-musk-accidentally-tweets-phone-number-to-john-carmack-has-god-of-war-voicemail-message