I definitely would let in for conversation, however my approach is more to understand than to tear down, probably because I'm not so sure about what I believe. I do understand how it could be enjoyable to get someone thinking different though. That's what those conversations are meant for and we'd all do well to lay aside our beliefs for the sake of a newly emergent view.
I like watching some of the street epistemology videos - it's basically what I'd need to do to talk to them. But I don't think i'd have the patience, and it would be creepy having strangers in my house who are hell bent on saving my soul. It's sometimes hard enough to have regular friends in the house let alone ones with an agenda.
But I did once get suckered into talking to a couple of guys back in England when I was pretty fresh out of college and recently convicted atheist. Somehow the ended up inside my home - probably because I lived in an appartment and it was awkward to talk outside- and I guess I talked to them for a bit and they gave me some magazine or book or something. These days I think I could torture them a bit, but honestly I wouldn't really bother these day unless I was seriously bored or mischievous. Fortunately where I live now there are no unsolicited calls ever.