When you adopt Hellenismos as a religion, you suddenly have a lot of extra festivals on the calendar. Funnily enough, that's the thing people are most shocked about. In addition to the fancy festivals, however, the Hellenistic base of worship is the monthly lunar calendar (the 'Mên kata Theion', 'sacred month'). Today, I'll present the basic, Hellenistic, monthly calendar. It's constructed from various ancient sources, and is recognized by many Hellenists today. Note, that this schedule was conglomerated with Hesiod's auspicious days, so--for example--the thirteenth of the month is sacred to Artemis, and a bad day for sowing.
First Decad - Waxing Moon - Mên Histámenos
1. Noumenia - Selene, Apollo Noumenios, Zeus Herkios and Ktesios, Hestia, and the other Theoi of the Household
2. Agathós Daímōn - Agathós Daímōn
3. Tritomênís - Athena
4. Tetrás - Aphrodite, Eros, Herakles, Poseidon, and Apollo
5. The Erinyes, Eris, and Horkos
6. Artemis
7. Apollo
8. Poseidon, Asklēpiós and Theseus
9. General holy day to honour the Theoi; special day to the Muses, Helios, and Rhea
10.