Just like “Guessing Baby Food,” it will involve people tasting various foods.
Know your audience, this may not be suitable for every Baby Shower.
Take six or more diapers, preferable newborn. Use ingridients like peanutbutter (smooth and or chunky), Nutella, almondbutter, yellow mustard, guacamole (exposed to air in will turn grayish-brownish), lemonade, or anything else you want to come up with. Spread those ingredients on numbered diapers an pass them around on a tray.
Have guests write down their guesses. You can decide whether you want to award whole point or fractional for a partial guess.
If you are going to be taking pictures, make sure to capture the expression immediately after the tasting.