and the remaining religious community is being selected for people who don't listen to such arguments, no matter what. So I'm not sure if elevator pitches are going to work very well.

Good point. This is probably the state of my wife, actually. If we "get into it" about religion (which I pretty much try to avoid) and I bring up anything in opposition, or worse, cite an eminent scientist working a field that could one day conclusively eliminate the remaining areas where the god hypothesis is invoked, a fairly standard response is: "It doesn't matter. I don't need to understand or explain everything."

Her strongest [verbalized] reasons for believing rest on the love she sees in the people in the community, times when she's felt some sort of transformation or insight result from prayer, and the fact that she sees her current lifestyle as having a "purpose higher than herself" coupled with an improvement from what she would say were shallow aims of her high school/early college/"pre-conversion" times.

So... yes, there's probably a good subset of those who will remain unconvinced. I was more looking for "elevator pitch" with respect to length, not necessarily with respect to its ability to convince.

In other words, a short conversation that begins and ends smoothly, briefly, and allows both parties to go on their way rather than the typical open-ended discussion/debate that follows. Think of it as a way to make my "pitch" that expresses 1) my clear non-belief but 2) doesn't lead into a back-and-forth pointless banter that I know ahead of time will not sway either of us.

I think Yvain's comment above about writing up a summary and then sending a link later on might be the best suggestion thus far (though I haven't caught up to all the comments below yet).