Frozen Mud Pie

In a bowl, combine cookie crumbs and butter. Press onto bottom and sides of an ungreased 9-inch pie plate. Refrigerate for 30 minutes. Spoon 1 pint of ice cream into crust. drizzle with half of the chocolate syrup; swirl with a knife. Carefully top with remaining ice cream. Drizzle with remaining syrup; swirl with a knife. Cover and freeze until firm. Remove from the freezer 10 to 15 minutes before serving. Garnish with dollops of sweetened whipped cream, if desired.