The mirror case allows you to stop holding your iPad as a camera and allow you to discretely shoot photos and presentations from a desk. You can allow students to record their presentations for future reference or as an alternative of presenting in front of a class. Teachers can record difficult concepts for students to review.
Use the Dewey iPad holder along with your data projector to turn your iPad into a document camera. As well as being a document camera, you can use to do live demonstrations or to record an action. It's great when devices can be used for multiple functions.
As simple as it seems, a stylus is a great tool to use with any tablet. It replaces the scrap piece of paper dug out of the recycling bin that you use with the almost broken pencil. You can use a drawing app to explain a complex mathematical problem, use in a group doing brainstorming and draw a pretty amazing drawing. It will give you better control than your finger will. I've also used them to create a digital signature to add to a document.