As a teacher, I'm always looking for ways to get my students to create and apply knowledge. DocAS is a versitile app that students or teachers can use in a variety of ways. It is an easy way to edit a document. It is also a new way to create a product. Think of a PowerPoint or Keynote presentation where the presenter or audience can annotate their presentation. You can also easily add voice recordings.
Here are step by step directions on how to create a doc AS document. I made a paper copy of this PDF and had 30 copies for them to use while they created their document. In this example, the students created their own visual analogies, but you can use it for anything. You could also use it to annotate maps, writing, or graphs. The directions have them learn how to take a screen shot with an iPad since our iPads were brand new, but you could have them capture the photo whatever way they know how. I found it was easiest to have my students email me their documents, but you could have them put it in their student folders as well.