I used to work with Peter, a bloke who was a christian to the core. Peter and I would occasionally travel together when working on the same project, and I could count on it that he would spend the travel time trying to convert me.
For long periods of time we grappled with the question of how to explain reality without invoking god as the creator and manager. As in "Without the existence of god, how do you explain . . ?". What usually followed was me attempting to impart the basics of evolution, and Peter attempting to debunk.
It took me a while to discover the best way to handle these arguments. I would reverse the question; I've been busting my brain to explain current scientific, evidence-based thinking on the nature of reality -- OK then, how does Peter explain the existence of a christian god?
With this approach, I could actually enjoy the discussions, thinking up sillier and sillier questions to pose. Where did God come from? When did god first appear? What did he do before he created the world? How did he cope in the dark before there was light. Apart from the Mary and Jesus event, how often does god have sex? Does he have other love children scattered throughout the universe? If not, why did he stop at one? It was the very best way to reduce Peter to a sullen and sulky silence without the need to simply tell him to shut the fuck up.