This idea by Chew on this particularly resonated with me.
I've made a decision to aim to buy only seasonal, local produce. Not only is it a shame to buy fruit and vegetables grown for shipping and a long shelf (instead of taste and freshness) but it goes some small way to reducing the impact on the environment. If you live in the NY area this wheel will tell you when certain things are in season. Smart.
No more strawberries flown in from some exotic location or apples grown in Israel!