Children should not be entertained and told what to do all the time. They need free play to be able to experiment, learn, build, demolish and make mess. This is always preferable outside.
Children of all ages need a sandpit and water. Bricks, logs, rocks, pine cones, seeds to grow etc.
When the children get stuck into a project of play do not pull them away to do chores, school or eat. Bring them lunch, a drink and your camera. This does not happen every day, so when it does let them go with the flow.
If it is winter and mizzy outside have a play area in the garage or a playroom. Have playdough, clay, lego, etc. out for them. These things can keep them busy for hours. The other things I have now are tools and wood for woodwork. We have no set projects and they can tinker and make whatever they like.
The other fantastic thing to have for kids is a veggy garden. The first veggie I would get them to plant is Swiss Chard. It is a dark green leafy veg that is very nutritional and easy to grow. Then I would plant strawberries, and parsley mixed in between each other as they are companion plants. Kids love strawberries and parsley looks so pretty when growing well. Parsley scrambled eggs are the best!
Another things I would grow is clumping onions. This is great as it can be used as a spring onion, chive or the bulbs can be chopped up as a traditional onion. I always have soup celery in the veg patch as well. This is always good to add to a soup.
Sheth loves to plant carrots and garlic bulbs. We all love baby tomatoes and they grow so easily!
There are so many options have fun with the kids, let them pick and eat off the bush, it does not get better than that!