Very easy, very refreshing:

Frozen Lemonade Pie
1 can (6 ounces) undiluted lemonade concentrate, thawed
1 quart vanilla ice cream, softened
1 graham cracker, gingersnap, or vanilla wafer crumb crust (9 inch)

Fold lemonade into ice cream. Blend well. Press gently but solidly into pie shell. Freeze until firm.

This one uses lemonade mix so is more economical.

Lemonade Pie
1 shortbread cookie crumb or graham cracker pie crust
1/2 cup Country Time lemonade mix
1/2 cup water
2 cups vanilla ice cream, softened
1 tub (8 ounce) Cool Whip topping, thawed

Stir drink mix and water until dissolved. Beat the lemonade mixture and ice cream in a large bowl until blended. Gently fold in whipped topping just until smooth. Freeze until the mixture mounds, if necessary, and spoon into the crust. Freeze 4 hours or overnight until firm. Let stand at room temperature 15 minutes before serving or until the pie can be cut easily. Garnish with lemon slices. Store leftovers in the freezer.