Somehow, AmericaIsAChristianNation.com was available as a domain name.
So an atheist website developer who saw The Unbelievers — a documentary featuring Richard Dawkins and Lawrence Krauss — purchased it and created this lovely page, quoting our Founding Fathers as they explain how the United States is most certainly not a Christian Nation:
You can submit your own quotations (with sources), so get to it!
(via Reddit)