If you run a restaurant inside a hotel, you know the pattern:
Families sit down. Kids get bored after 20 minutes. Parents rush the meal. Bill paid. Everyone leaves.
Many restaurants give kids a sheet of paper and some crayons. Buys about 0-5 minutes of extra time. At least with my kids 😀
But in New Zealand, several restaurants gave our kids something called a “smarty bag”.

Inside the bag:
Basically, a small entertainment kit.
Our two kids were busy right away, and we stayed at the restaurant significantly longer than usual.

I checked the company behind it. They have already sold 4 million bags.
One bag costs about €1 and the minimum order is 100 pieces. That is one of the cheapest revenue management tools you will ever buy.