I'm seriously considering doing a take an atheist to church experiment, if there's enough interest.
I would solicit invitations to Church (an invitation that includes buying me lunch would certainly have an advantage.) I will choose one invite to accept, and attend a church service or mass or what have you, Muslim, Christian, Konko, Jewish, Buddhist, whatever.
I will be respectful and attentive. My respect and my love for the theists in my life, including those in my family will lead me to behave myself. I'm interested in showing and receiving respect, not in poking fun or agitating.
I will make it clear that trying to convert me will not be likely, (though such efforts are perfectly welcome) but I will encourage open, frank discussion of things like prayer in school, and the ten commandments in government building.