1. Line 2 (15- x 10-inch) jelly-roll pans with parchment or wax paper. Prepare angel food cake mix batter according to package directions. Pour evenly into prepared pans.
2. Bake at 325° for 15 to 20 minutes or until a wooden pick inserted in center comes out clean. Cool in pans on wire racks 10 minutes. (If baking cakes in 1 oven, bake on middle 2 racks for 10 minutes; then switch places, and continue baking for 5 to 10 minutes.)
3. Sift 1/3 cup powdered sugar evenly over each of 2 (24- x 18-inch) pieces heavy-duty aluminum foil.
4. Loosen edges of cakes from pans. Invert each slightly warm cake onto a prepared foil piece. Carefully remove parchment paper, and discard. Place a cloth towel on top of each cake. Starting at 1 long side, roll up foil, cake, and towel together.
5. Chill rolled cakes 30 minutes or until completely cool. Unroll and remove towels. (Keep each cake on foil piece.)
6. Stir crumbled graham crackers, Key lime juice, and 1 tsp. grated lime rind into softened ice cream. Spread half of ice cream over top of 1 prepared cake on foil piece, leaving a 1-inch border, and roll up jelly-roll fashion, ending seam side down. Wrap cake roll with foil piece, sealing at both ends. Place in freezer. Repeat procedure with remaining ice cream and prepared cake on foil piece.
7. Freeze cake rolls at least 8 hours or until firm. Unwrap and frost each evenly with whipped topping. Serve immediately, or freeze cake roll 1 hour or until whipped topping is firm; rewrap with foil, and freeze until ready to serve. Garnish, if desired, and serve with Raspberry Sauce.