1. One day before serving, hull strawberries. Cut two 1-inch berries in half; set aside, Very thinly slice remaining berries into a small bowl. Toss with sugar. Add halved berries to top; cover tightly and refrigerate overnight. 2. Next day, place a berry half in each of 4 chilled 8-oz punch glasses or mugs. Thoroughly strain sugared berries, allowing juice to flow into 2 quart pitcher or punch bowl. (Strained berries may be reserved for another purpose.) 3. Stir sparkling water and grenadine into juice. Pour into prepared glasses; serve immediately. If desired, serve punch over ice cubes.