The Farm Effect truck serves specialty sandwiches with names like Divine Bovine, which is roast beef, gorgonzola and watercress on whole wheat, and Farmer’s Daughter, with chicken, smoked gouda and arugula. Owner Stephen Hambleton and his brother, David, also sell potato salad, peanut butter flourless cookies and homemade kombucha. Sources include organic chicken from family-run Hambleton Farm in Warrenton as well as fresh bread from Moving Meadows Farm Bakery and Firehook Bakery.