Greece
Basically, nearly every village in Greece has a church named after a saint, and when it is that saint's day, the village usually has a party.
Ikaria is justly famous for its panagiria, which tend to start at midday and end when the last musician drops off his/he chair from exhaustion, some time around dawn the next day. Food is usually basic: roast goat, rice, chips and salad, with wine or beer to wash it down. Music (always live) tends to be predominantly nisiotika (traditional island music) with a fair amount of rebetika thrown in. All ages attend (at one, the youngest person at our table was my daughter, then aged 6 months, and the oldest, my wife's aunt aged 102!).
You will drink and you will dance, even if you normally do neither. Fantastic fun, and a great chance to participate in a folk culture that is very much still alive.
Ask around when you get there or check this site:
www.island-ikaria.com/
Search Been there