CSA. And while I couldn't answer most of them (soon, I hope!), I did recently find this Peak-Season Map.
Since last fall, I have been trying to eat only in-season fruits and veggies, which hasn't been too hard, minus the apples. Always.want.apples.
This map allows you to pick your state + month and then generates peak fruits and veggies. Summer ones seemed pretty obvious, but I had no idea Brussels sprouts were in season in December. Cha-ching!