And there are many people that continue to be religious even after becoming atheists. "The little book of atheist spirituality" from André Comte-Sponville, touches on this subject, and many others. I'm would also call myself an atheist-catholic.

I remember a joke in the book where two rabbis are discussing the issue of god's existence during the supper, at the end, they both agree that god must not exist and then go to sleep. At the next day one rabbi finds the other doing his early prayers and confounded asks him why he is praying if there is no god, to which the other one answers "what does praying has to do with god?".