On Fridays from June through October, there's a Farmers Market on the East side of USDA's North Bldg from 11AM to 2PM. Vendors had fruit, vegetables, herbs, breads, cheese, flowers, & preserves for sale. Rainbow Italian Ice had a long line. I tried a combo of passion fruit and mango ice. Outstanding! Are Rainbow Italian Ices available elsewhere? The tangerine looked good, too.
Closest metro: Smithsonian