Tell him you have met Jesus, and he should come have dinner with you. 5:30, when Jesus gets off from his landscaping job.

I once said "I'm an Atheist. If god wants to talk with me, have him text me. If he's god he knows my number. We can do lunch. I'll buy."

Yes, just stop them in their tracks....and tell them you are an atheist, it usually stops them midstream and renders them speechless ! I am an old hand at it, it works every time.

You're different from me. I just don't care.
I act bored, mumble, "Um-hum, that's nice," then immediately leave/shut the door/hang up, etc.

I am brusque but with a smile. "Sorry, I've got my own religion" I say. "I'm good." And turn/walk away/close the door.

I feel you. I often feel tongue-tied when it comes up, even when I have no reason to think the person would be hoste.

I'm kind of an asshole. I never fake interest. I'll either argue against their faith or, more frequently, tell them flat out I'm atheist. If they want to try and "save" me at that point, I'll usually give them a few mins to make their pitch so they can report back to their masters that they at least tried to convert a heathen.

Sounds like you're just a nice guy.

Being polite is not necessarily being a fraud. I used to go to, and liked, the Unitarian Universalist Society or some use Church, etc. Very welcoming group from agnostics to atheists to liberal believers. So, I usually admit to such people that my family are Unitarians, and most haven't a clue. Jehovah's witnesses are the funniest because they will ask for some explanation, so I say they started as non Trinitarians, to which they suddenly get excited like we are long lost cousins. Too which I reply not quite and move on.

Ask questions! Have some ready for next time.

Why do faith healers not visit hospitals?
If money is the root of all evil, why dis god need it?
Why do good Christians not have longer life experiences?

"I'm an atheist," I say firmly and walk away.