Cover with plastic wrap and chill glasses at an angle until Jell-O is set.
Fold whipped topping into remaining (1/3 cup) Jello-O
Refrigerate until ready to use.
Spoon topping mixture into glasses of set Jello.
Garnish with sprinkles and serve.
Notes
If you're on Weight Watchers, this dessert is 3 Points. To lower the Points, you can use sugar-free Jell-O to reduce the Points to 1. Using fat-free Cool Whip reduces the Points to zero.