Go to a large family gathering. (Or a similar gathering. Borrow someone else’s large family if you don’t have one.) When somebody decides you are all going to pray together with bowed heads, start to bow your head so everybody else sees you doing it, but after everyone’s heads are supposed to be bowed, unbow your head.
Have a look around.
You will find yourself looking at a few other people who are also looking around. Those are the other atheists.
Introduce yourself after the prayer, and then you can make arrangements for an orgy or a baby-roast or something.