You might want to read _cows, pigs, wars, and witches_.

The major festivals are all about food.

fall festivals--harvest time, slaughtering time, eat as much as you can 'cause it can't all be stored

winter festivals-- eat it before it spoils

Spring festivals-- eggs oh my gosh, the eggs are back again.

And that's for places with the four seasons like in North America.

I'm sure there's a different way to do it when the Wet/ Dry is the important cycle rather than the temperature.

Seriously Marvin Harris was a heck of a guy. http://en.wikipedia.org/wiki/Marvin_Harris