CHOP 8 of the cookies coarsely; set aside. Finely crush 20 cookies. Mix cookie crumbs and margarine; press firmly onto bottom and up side of 9-inch pie plate. Refrigerate until ready to use.
PLACE marshmallows and milk in 2-qt. saucepan; cook on medium heat until marshmallows are completely melted and mixture is well blended. Cool completely. Gently stir in whipped topping and the chopped cookies. Spoon into prepared pie crust.
REFRIGERATE several hours or until firm. Store leftover pie in refrigerator.