Explaining Christianity to a 5-year-old atheist

This is in response to a lot of questions Andrew had about whether Christianity makes sense or is worthy of concern.(The challenge was to EILI5, I suppose this is as simple as I can make it for now.)  I am coming at this in an admittedly unorthodox way. I don’t know that I believe in a personal God, or even really know what that could mean, so setting aside this fundamental Christian doctrine, i.e. whether God is either personal or ethical. I will try to put the other rudiments of Christianity in a way that would make sense to the average five-year-old (or 35-year-old) deist, atheist, or pagan.