Satanism

Let's become satanists. It's the only religion that actually makes sense. Atheism and satanism go hand in hand.
You don't worship anything, just live by what Satan as a concept represents.

    The Nine Satanic Statements
1. Satan represents indulgence instead of abstinence.
2. Satan represents vital existence instead of spiritual pipe dreams.
3. Satan represents undefiled wisdom instead of hypocritical self-deceit.
4. Satan represents kindness to those who deserve it instead of love wasted on ingrates.
5. Satan represents vengeance instead of turning the other cheek.
6. Satan represents responsibility to the responsible instead of concern for psychic vampires.
7. Satan represents man as just another animal, sometimes better, more often worse than those that walk on all-fours, who, because of his "divine spiritual and intellectual development", has become the most vicious animal of all.
8. Satan represents all of the so-called sins, as they all lead to physical, mental, or emotional gratification.
9. Satan has been the best friend the Church has ever had, as He has kept it in business all these years.

Good idea, except that if you believe in Satan, you're no atheist.

The vengeance part can get messy.  I prefer lazy vengeance, that is, if I get around to it.  Less suffering in the long term that way.