An Open Air Market will be held Saturday, June 13.   Sponsored by the Hancock County Park Board, the Market will take place from noon til 5 p.m. at the Park & Recreation Complex on Gas Valley Road, New Manchester.    Food offerings will include Cousins Lobster,  MJB Barbeque, Dees Dogs and Gelato.  Over 30 vendors will feature their wares.   A rain date has been set for June 20.