Kids love this, and it's easy to let them help you prepare it. It's also great party food. You can make it earlier in the day (although maybe not with the avocado), wrap well in plastic wrap, and refrigerate until serving time.
1 loaf soft bakery French bread
1 1/2 avocados, mashed with salt and lemon juice
6 oz. turkey lunch meat
5 slices Cheddar cheese
Cut the top off the loaf of bread and pull out some of the soft insides to make room for fillings. Fill with remaining ingredients; replace top and slice. Feel free to substitute your own favorite filling.