Place Oreos in a blender or food processor, blending them until they are crumbs.
In a medium mixing bowl, mix melted butter and cookie crumbs together.
Press crumb/butter mixture into a 9x13-inch baking dish.
In a large mixing bowl, beat cream cheese and 8 ounces of Cool Whip until smooth.
Add 1 ½ cups of confetti cake mix and beat again until smooth.
Stir in ¼ cup sprinkles (optional).
Spread cream cheese mixture on top of crust.
In a large mixing bowl, beat pudding mix and milk together until it thickens.
Add remaining ½ cup of confetti cake mix and beat until smooth.
Stir in ¼ cup sprinkles (optional).
Spread pudding layer over top of cream cheese layer.
Spread remaining Cool Whip over top of pudding layer.
Add ¼ cup sprinkles on top (optional).
Refrigerate for 2 hours prior to serving.
Store in an airtight container in the refrigerator.