Heat margarine in heavy 3 qt. Saucepan over medium-high heat until melted. Stir in sugar (mixture will be very granular). Stir frequently with wooden spoon, 4 to 5 min. While mixture melts & begins to turn golden (sugar & margarine may separate). Continue cooking 1 to 2 min., stirring constantly, until mixture is no longer granular (mixture may still be separated; do not overcook); remove from heat. Quickly add cereal. Mix until cereal is completely coated. Immediately spread on ungreased cookie sheet. Cool completely; break into bite-size pieces. Store in airtight container.