Big Smile Pays Off Here- Marion D. Mack of West Roxbury has her smile measured by Bill Diedering of Needham, in a "Standing Broad-Smile" game yesterday at a Unitarian youth meeting at the Arlington Street Church. Front row, left to right, Ken Gardiner, Brookline; Sylvia Doble, Hingham; Miss Mack and Diedering. Back row, Wally Chipman, Hingham; Nancy Clark, Nancy Benway and Bill Whittemore of West Roxbury, and Betty Ferguson, Boston.