The best foods are usually grown at a nearby farm.
Farmers' market are usually located in designated parking lots, or other public places on a a specific day or days each week. It is a place where the local farms around your area bring their in-season, fresh produce to sell directly to you.
This is a great outing for the kids and a chance to talk with local farmers about what is in season. Don’t be afraid to ask if they use pesticides or fertilizers. Some farmers' markets even have entertainment and special events for kids!
Here are some sites that offer listings of local farmer's markets.