Here is a new website I heard about last week called bookcreator. It's a great way to allow kids to create a wide variety of books and have an authentic audience. Below is the link to different ways to use book creator. You can sign up for free, but there is a limit to how many books can be created. It could be a great extension activity for kids who need a little something extra.
Here's a sample of a book I created for an example.