Nova Roma
Nova Roma is an international Ancient Roman revivalist and reconstructionist organization. Nova Roma states that is promotes "the restoration of classical Roman religion, culture, and virtues" and "shared Roman ideals". It provides various online resources.
It has been referrred to as a polytheistic reconstructionist community. Because it has a structure based on the ancient Roman Republic, with a senate, magistrates and laws enacted by vote of the comitia, and with its own coinage, and because the Nova Roma Wiki states that the group self-identifies as a "sovereign nation", some outside observers classify it as a micronation.