CRUST:

8 graham crackers, crushed
2 tbsp. sugar
4 tbsp. butter, melted

FILLING:

2 (8 oz.) cartons yogurt
1 (8 oz.) carton Cool Whip, thawed

Mix ingredients for crust well and put into pie pan. Bake at 350 degrees for 10 minutes. Mix filling ingredients well and spoon into pie shell. Freeze at least 4 hours. Remove from freezer to refrigerator 1/2 hour before serving, to soften slightly before cutting.