There is currently only one main resource for use by the neo-Hellenic Polytheists, unquestionably the more eminent one is Hellenic Month Established Per Athens (HMEPA) Calendar online. The HMERA Calendar is based on the monthly and annual festivals of the ancient Athens 800 - 323 BC. You can read its 'about' page here. Another Calendar which I am expecting soon to be available is will be created by The Hellenion, a US-based religious organization dedicated to the revival and practice of Hellenic polytheism. The Hellenion's Calendar is the most functional ancient Greek Calendar at the Web today. The original Calendar's Time Zone is the Pacific Time (GMT-08:00). For a PDF or HTML and additional information please visit Hellenion's Calendar web-site. Important Note: The following festivity of Heliogenna which is listed within the Hellenion's Calendar below is a modern creation by Hector Lugo for the Winter Solstice (you can find more information at Hellenistai Wiki). For more information for the Classical and (late) Hellenistic / Roman eras' festive for the (new) Sun and Winter Solstice see our label 'heliou-genelthion'.