Combine Oreos (except for reserved) and 1/4 C. melted butter together. Press in the bottom of a 9x13 inch casserole dish. Freeze. Take ice cream out of freezer to soften. Melt chocolate syrup, 1 stick butter and condensed milk in a pan. Bring to a boil and cool. Spread ice cream over cookie crust. Freeze for 2-3 hours. Pour chocolate mixture over ice cream layer. Freeze until firm. Spread Cool Whip over the chocolate layer and sprinkle with reserved cookies. Freeze until firm. Serve.