Place melon in a blender container or food processor bowl. Cover and blend or process until pureed. Stir together melon puree, yogurt, honey, and snipped pineapple sage in a medium mixing bowl.
Freeze mixture in a 2-quart ice cream freezer according to manufacturer's directions. Ripen for 4 hours. (Or, transfer mixture to a nonmetal freezer container. Cover and freeze for several hours or until almost firm. Break mixture into small chunks; transfer to a chilled bowl. Beat with an electric mixer until smooth but not melted. Return to container. Cover and freeze for 6 hours or until firm.)
To serve, scoop mixture into individual dessert dishes. If desired, garnish each serving with pineapple sage leaves. Makes about 4 cups or 8 servings.