Sandra (nee Cohan) and Joseph H. Ball marked their 50th wedding anniversary on June 1 with a family luncheon. The couple has three children: Robert Ball of McLean, Va.; Yelane Rosenbaum; and Nanelle and Robert Meyers, as well as eight grandchildren. Mr. Ball is the founder and owner of one of Philadelphia's longest-established (51 years) advertising agencies. He is also a newspaper publisher, and producer of a talk-radio show. Sandra is a retired preschool teacher and a former president of the philanthropic organization Golden Slipper Women.