Out of curiousity; has anyone here ever successfully convinced a religious person that they were wrong, and what happened next? I mean it's theoretically possible, but usually seems to occur when you have the zeitgeist of pondering how you life doesn't match up with your religion. I would postulate it's very hard to convince someone who hasn't recently had a traumatic event (not that that is, necessarily, by any means the best time to raise such questions) or some other cause of uncertainty, who is also willing to debate. In other words, anyone achieved this with someone who's content to some degree?
While I can't say for certain there hadn't been any other motivators, I can also report a case. Much like Palsch, it was in a situation where actual debate was able to occur; myself and several others used to spend a lot of time on the FSM blog (not the forums, but responding in the actual blog comments; meant we dealt with the *really* crazy ones mostly). Anyway, one group of creationist christians started posting the usual "You're god is obviously fake, he's a mass of spaghetti!" and "You're all going to burn in hell" schtick. Most of them left after a little while, but one stuck around and started debating. As he was a YEC, a lot of his arguments involved things like arguing how you can't use carbon dating to determine the age of the planet, and evolution can't produce structures like the eye etc.
At that stage, I worked in a geochronology lab, so I was able to give him a very clear breakdown of how radioisotape dating worked, and we had another poster who worked as a microbiologist, who set him straight on his miscomprehensions there. Anyway, we eventually persuaded him that the idea of a Young Earth is farcial and that things like morality don't need a god, and that was the last we heard of him for 6 months.
When he came back, he said he had become an atheist, and wanted advice on how to reveal the fact to his devout mother. Apparently, after we had parted ways he'd realised that he didn't know as much about both the world and his own faith as he had thought, and had started doing some reading on the subject.
So it is possible, but it's rare, and it requires an open mind on the topic, something that is often lacking on both sides of the fence.