What about Paneyiri? That's always been a great venue for dancing on the island where I go. Don't they do that in mainland Greece?

On the feast day of the saint to whom any church is consecrated, the parish hosts a religious festival, their annual "paneyiri." It usually includes live bouzouki music and dancing in the town square till late into the night. It's a public event, offered up by the parish in honor of their patron saint, so anyone can join in the dancing.