What can atheists do / not do?

[Ryft]

Do you atheists have any rules about what you can or can't do?

What atheists can or cannot do depends rather directly on the belief system they have—which is not atheism. Many are Humanists, others are Buddhists, a couple here and there might be Nihilists, etc. Those are belief systems and worldviews. The only thing they have in common is atheism, which is not a belief system, worldview, philosophy, religion, etc. It is very simply a "no gods" presupposition, upon which a belief system is built. As I have said elsewhere (and you would do well to understand this point):

Atheism is defined as the "godless" fundamental starting point (presupposition) at bottom of one's worldview, upon which his metaphysics, epistemology, ethics, and so forth is built. It is "godless" by virtue of the very term itself (Gk. atheos, which means "without deity" in the same way that asymmetrical means "without symmetry"), and it is presuppositional because nothing justifies it (for the very criteria by which he justifies anything already presupposes No Deity Required; if deity is required at any point, atheism is precluded).