Prepare and bake cake mix according to package directions for a 9x13 inch pan. Poke holes in cake while still hot with a fork.
Make gelatin with boiling water, then stir in lemon-lime soda. Pour hot mixture over cake. Cool cake completely, then refrigerate for at least 4 hours before frosting.
Beat together instant pudding and milk until thick, then pour over cake. Frost cake with whipped topping. Keep cake refrigerated until ready to serve.
