Over at Science Blogs, GrrlScientist has posted what she calls the "top fifty atheist t-shirt and bumper sticker aphorisms," but I don't think they are exclusively "atheist." I can say with confidence that Unitarians, Universalists, and other nonfundamentalists can laugh at them too, and I daresay even a few more religious types, if they can truly laugh at themselves. Some of my favorites:
Abstinence Makes the Church Grow Fondlers
Honk If Your Religious Beliefs Make You An Asshole
Intelligent Design Makes My Monkey Cry
There's A REASON Why Atheists Don't Fly Planes Into Buildings
"Worship Me or I Will Torture You Forever. Have a Nice Day." God.
People Who Don't Want Their Beliefs Laughed at Shouldn't Have Such Funny Beliefs
Threatening Children With Hell Is FUN!
GOD - APPLY DIRECTLY TO FOREHEAD!
God Doesn't Exist. So, I Guess That Means No One Loves You.
Science: It Works, Bitches.
I Gave Up Superstitious Mumbo Jumbo For Lent
My Flying Monkey Can Beat Up Your Guardian Angel
Every Time You Play With Yourself, God Kills a Kitten
Praying Is Politically Correct Schizophrenia
I Was An Atheist Until The Hindus Convinced Me That I Was God
The Spanish Inquisition: The Original Faith-based Initiative
If we were made in his image, when why aren't humans invisible too?
JESUS SAVES....You From Thinking For Yourself
Every Time You See a Rainbow, God is Having Gay Sex
I Went to Public School in Kansas and All I Got Was This Lousy T-shirt and a Poor Understanding of the Scientific Method.
The Family That Prays Together is Brainwashing the Children
No Gods. No Mullets.