Android Mobile App Dev Tutor

I need an expert Android developer who also knows how to teach beginning programmers. You will find an existing cool Android app in Creative Commons (or supply one of your own) and turn it into a series of progressive activities for a three day class. You will heavily comment the code, and write tutorial steps, taking the student by the hand as they build this app one feature at a time. Time is VERY short for this project, so there is no time for you to code a new app by scratch. All focus must be on using an existing app and turn it into a 3-day activity. Please respond with a sample of a tutorial you have written, and a description of the app you have in mind for this project.