As long as you are creative enough then you can enjoy this stuff with the imagination that you can use in making all this things. A lot of kids like summer because they know that this is their time to enjoy outside with all their friend running around and enjoying the presence of each other. Let them have the freedom of having fun outside and enjoying the world right now because they are still young because if they are going to be old already then it would be really hard for them to get some time to enjoy things because of the responsibilities that they have to face in the adult life.
Since summer there will be no school, they would be able to enjoy a lot of their time and they would have a long time that they can have fun. You should let all your kids go out and enjoy the summer with the kids in the neighbor, do not just let your kids stay inside playing their gadgets. It is better if you can have some recreational sports or games in where the kids will be able to learn new skills while having fun.
There are a lot of things that you can find fun with, you will just have to make it more nice and you can use your imagination. If you want to know more then you have to read more here so that you can find the nice varieties of activities.
Right now that they are still young, we should make sure that they are going to enjoy life to the fullest within all the potential that they can reach so that they are not going to regret growing up and not having something to look forward for when the summer is going to be back again.