I have a friend who runs a drone photography business called PurpleFinch PhotoDrone. As a favor, I offered to make an AR app that recognizes his business card and displays a flying drone. Once the app is opened, the user will be able to look at (point the camera) the company's business card, and a virtual drone will appear and fly around. It'll be a cool little promotional thing he can share with clients and friends. The following is a screenshot of his website:
You can follow along with this specific project (the assets are available for download from the publisher's download site for this book). Or feel free to do something ...