George Carlin was the first celebrity I ever knew was atheist. He was among the first few I knew, other than myself, who were atheist at all. Possibly the very first one at all.
To this day, he's still done better than just about anyone at giving religion the criticism it is due. I think he should have been included in the group labeled "New Atheists" and should have been considered one of the Four Horseman (not to say any of the four given that distinction were undeserving, of course). His words against religion did precede theirs, after all.
I had heard of Carlin before, but only marginally. I first learned of his stance on religion when I saw his now famous bit about religion being the best at bullshit.
In that rant, he compared god worship to sun worship and praying to a god to praying to Joe Pesci. He made fun of the concept of Hell and how it's supposed to be a punishment from an all-loving god. He made fun of churches' need for money.
He said everything I already felt but had never expressed and had never heard anyone else express. Until then, I thought I was the only one. Seeing this rant of Carlin's changed my life. That was the day I learned I wasn't alone. I'm a fan of stand-up comedy, and George Carlin was among the best of all time. But it was this bit from him for which I will be eternally gratefully.
Well, at least as close to eternal as a mortal can get.