Combine the crushed Oreos and melted butter in a large bowl with a fork. Press the mixture evenly into two 9-inch pie plates.
Spread the softened coffee ice cream into the pies over the crusts so that you have at least 1 1/2 inches of ice cream. Place in the freezer.
Combine the fudge topping ingredients in a medium-size heavy saucepan. Stir over low heat until completely melted and combined. Remove from the heat and let cool.
When the ice cream is really solid (about 3 hours or overnight), pour the frudge topping evenly over each pie. Wrap with plastic wrap and freeze again until the topping is solid. To store them after they are frozen, wrap tightly in plastic wrap and then aluminmum foil to keep them fresh.