In a large bowl, combine the cereal, brown sugar, peanuts and coconut. Drizzle with butter; stir until combined.
Press half of the mixture into an ungreased 13-in. x 9-in. dish. Cut ice cream into 3/4-in.-thick slices; arrange evenly over crust. Top with remaining crumb mixture; press down lightly. Cover and freeze until serving.
Editor's Note: Purchase a rectangular-shaped package of ice cream for the easiest cutting.