Here's a Boredom Buster idea for kids:
Prepare some "grab bags" out of brown paper bags. Each bag can contain supplies for a simple project, ingredients for a simple recipe, a yo-yo and an instruction book for doing yo-yo tricks, new coloring book and crayons, and so on. Put the bags away for those days when the kids are inside and bored. Pull out the bags, and let them each pick a grab bag and have some instant fun!