PREPARE cake batter and bake as directed on package for 24 cupcakes. Cool in pans 15 min. Remove from pans to wire racks; cool completely.
SPOON 3/4 cup Cool Whip into each of 4 small bowls. Tint each with food colouring. Frost 6 cupcakes with each colour Cool Whip.
TAPE 1 piece of ribbon to bottom of each cupcake liner. Arrange cupcakes on large platter just before serving. Tie loose ends of all ribbons together; place on platter. Refrigerate leftovers.