Really interesting piece in Religion Dispatches by Christopher Stedman, Humanist Chaplain at Harvard University, who argues for the inclusion of atheists in the Interfaith Movement:
To atheists concerned about being seen as “just another faith” and worried that interfaith isn’t an avenue for substantive discourse: I encourage you to give it a shot anyway, and be vocal about where you stand. I cannot begin to recount all of the times interfaith work has opened up a space for robust conversations on problematic religious practices and beliefs—in fact, it has been a hallmark of my experience working in the interfaith movement. All the more, it has allowed me to engage religious people about atheist identity and eradicate significant misconceptions about what atheism is and what it isn’t…
In my experience, interfaith work doesn’t require that people check their convictions at the door—it invites people to try to understand and humanize the other. It’s a worthy goal, and if the only thing keeping some atheists from participating is a semantic disagreement with the word “faith,” I think that is a missed opportunity.
Yedid Nefesh 
I want a definition of “religion” and one of “faith” that will make sense out of this position. I thought that all the religions focus on faith and trust in one or more Holy Beings, usually called God, I’m under the impression that the word “atheist” means absence of Deity. How can that fit?
Maybe it depends on one’s “religion.” For many Jews observance is a matter of culture, habit, fetish whatever. They may or may not have “faith” in (pray to) anything supernatural.
Here’s how Satan sees it, over at Satan’s Blog: http://wp.me/p14HPl-VH. You might find it interesting.
Most religions focus on faith or trust in a divinity, but there are some that don’t. Mahayana Buddhism would be one example, although other Buddhisms differ. Arguably, Reconstructionist Judaism is another, given the way “God” is radically redefined in Kaplan’s thought (as I understand it, anyway), so that we’re no longer talking about a Being in any real sense of the word.
I suspect there are a lot of atheists who nominally affiliate with most world religions, belonging without believing in order to reap the social solidarity of affiliation. As secular and religious humanism find a place in the Interfaith conversation, they might find a way to be “out” without stigma or isolation.
Rabbi David Mivasair forwarded your message to me, thinking I should appreciate it. Yes, I am interested. I like your saying that atheists are God’s opposition, withouot the word ‘loyal’. In communist China and the former USSR, atheists were the government and God was the opposition.
I am neither communist nor atheist. I am a Confucianist and a Buddhist. Confucius declines to speculate whether God exists or not. He says humanity has priority.
Rabbi David told me that Jews do not mind sceptics because Jews also question God. Yes, I have read Jews arguing with God.
Atheists are bravely honest in religion-dominated countries. They are powerful antidotes for religious fanatics drugged by religion cocaine. Sceptics are gentler antidotes.
Interfaith needs sceptics.