If you want to engage your child and yourself in an interesting summer project, then you can start a home based small scale project by building a backyard fort. It can act as a wonderful playhouse for your kid and it can keep your kid engaged for long hours during the summer breaks. You can build a tree fort or a tree house as well if you have a sturdy and safe tree in your backyard.
First of all, get all the materials needed. Wooden forts are the best and they have a traditional and aesthetic feel too. You need to have wood planks, industrial glue, pins, nails, wood cutting equipments, and other necessary tools for wood work. Have a blueprint ready for the work and get a 3D image design free from any online source. This will help you get a better idea and you can get started in no time.