American Creation blog, and one of the major recurring topics over there regards the religious beliefs & practice of the American founders. Were they Christians? What kind of Christians? Devout? Lax? Nicene orthodox? Unitarian? You get the idea.
Apart from the very real difficulty of accurately describing the religious views of some of the founders (who, for example, can coherently describe whatever Thomas Jefferson happened to believe at any given moment?), this kind of questioning is quite popular. It shows up quite a bit in constitutional law scholarship discussing the First Amendment's religion clauses and the role of faith in public life. I myself wrote a law review article* awhile back that spent a little time looking at some of the religious beliefs held by Jefferson & Madison that likely influenced their views on church-state separation, for example. And yet...
Over at The American Conservative online, writer Paul Gottfried argues that this whole line of questioning is mistaken: Was George Washington a Christian? According to Gottfried's approach the relevant question isn't what did the founders believe? rather it is what kind of social and political order did the founders intend to create? Gottfried has some thoughts on both questions, and his ideas are well worth pondering. I particularly am struck by his framing of the debate about religion and the Founding Era. Worth a read.
* = Mark DeForrest, The Use and Scope of Extrinsic Evidence in Evaluating Establishment Clause Cases in Light of the Lemon Test's Secular Purpose Requirement, 20 Regent U. L. Rev. 201 (2007-2008). Also worth a read, even after the passage of years since its publication.