Another alternative to the false trilemma of CS Lewis's is... Legend. Made up in whole or in part after the fact. (Any part not made up would be a perfectly normal hominid.)
I typed out a rather elaborate response to this question guised in the form of Perennial Philosophy, which I'll link here if anyone's interested.
I love the irony in the contrasting possibilities for Jesus. Either he was the son of God, and the meekest and humblest being ever to walk the earth; or he was some guy claiming to be the Son of God - perhaps the least meek and humble claim a man can possibly make...
Jesus is Mithra's little brother.
This just in Jesus's Dad hates doves.