Cooking with Chef John Wilson at Barrington Hall.  Themes:  August 7:  A Summer Cocktail Buffet with Lemon Drop Martinis; August 21:  Sauces.    At the end of each class, participants will dine on the meal they prepared.  6:30-9:30pm.  $50/person/class.  Reservations required.  Barrington Hall, 535 Barrington Drive, Roswell.  More info/reservations:  770-640-3855.