Place three 16-ounce glasses on angle in standard-size loaf pan. Leave 3 other glasses upright.
In a blender, combine orange sherbet and 1/2 cup lowfat milk. Blend until smooth but still thick. Starting with upright glasses, carefully spoon about 1/3 cup of mixture into each glass. Transfer glasses to freezer. Into each of the 3 tilted glasses, spoon 1/3 cup mixture, being careful not to get any drips on sides of glasses. Transfer loaf pan to freezer. Freeze glasses 1 hour or until sherbet is firm.
When layers are firm, in blender, combine lemon sherbet, 1/2 cup lowfat milk and yellow food coloring. Blend until smooth but still thick. Spoon 1/3 cup mixture into each upright glass and each tilted glass. Freeze 1 hour or until firm.
When layers are firm, in blender, combine lime sherbet, 1/2 cup lowfat milk and green food coloring. Blend and spoon into glasses as above. Freeze 1 hour.
For final layer, in blender, combine raspberry sherbet and remaining 3/4 cup milk. Blend until smooth but still thick. Fill each upright glass with 1/3 cup mixture. Place tilted glasses upright; fill each with remaining mixture, dividing equally and covering green layer. Freeze 1 hour or overnight. Garnish with skewered fruit, if desired. Makes 6 treats.