I'd already been out as an atheist for a really long time, but there was one occasion when I had an opportunity to "come out" to my very catholic family.

It was during a particularly heated religious discussion, there were a lot of negative things being said about gay people, and I just couldn't take it anymore.
So, I piped up "Well, I'm an unapologetic atheist, and I think it's really hypocritical for anyone who claims to believe in any god to slam another of their god's creations." The conversation screeched to an abrupt halt, as you would imagine.
Finally, my 100 year old great-uncle (at the time) said. "That makes more sense than anything anyone else has had to say. It is hypocritical."
No one else had anything to say, and the subject was changed.
Uncle Johnny had spoken, and since we were in his house, no one dared challenge him, or me. It didn't hurt that I was his favorite grand-niece.
To this day, none of those present that day have ever had anything to say about my atheism. At least not to my face anyway.