Farmer’s Markets are a great source of fresh fruits and vegetables. Whenever I am traveling, I always check out Local Harvest to find the nearest farmers market and the hours. They also are a great place to check out local farms that offer shares for the season (Community Supported Agriculture, or CSAs).
My favorite market is the Port Washington Farmers Market, not only because it is close to home but because it it the only all-organic farmers market in New York State. If you are New York City, Greenmarket offers local and organic produce for sale in all the five boroughs. Check them out: http://www.grownyc.org/greenmarket