This is the 50th anniversary of the American Atheists – that’s the hard-line atheist group with those in-your-face billboards that show Jesus in the manger with the words "You Know It's a Myth."

It's coming at a time when the number of non-believers is growing in America – especially among the ones under 35 – according to the Pew Research Center.

Tomorrow, the American Atheists are meeting to note their half-century mark and to talk about the future. So, which way is this movement headed?

David Silverman is president of the American Atheists.

"We only have one thing that binds us: that’s our lack of belief in God….You can be Republican or Democrat… rich or poor… pro choice or anti-abortion and still be an atheist. You can be pro American or anti American and still be an atheist."

So, what’s a movement to do?