• Prepare an ordinary white cake mix according to box directions. Use a sheet cake (9 x 13) baking pan. • Poke holes with a fork or a pair of chopsticks when the sheet cake gets cool. Holes should not go all the way through cake to the bottom of the pan. The entire cake should be perforated this way with holes every 1/2 - 3/4 inch (1-2 centimeters). • Jello for Jello Cake. Prepare a large box of flavored gelatin. Do not chill. • Pour cooled gelatin liquid evenly over entire cake. Holes in the cake allow gelatin to seep into the cake. • Place the cake in the refrigerator until gelatin firms, about 3-4 hours. Spread a whipped topping over top of cake, decorate with colorful candy sprinkles (optional) and serve!