My intention was to make a game very similar to yvoschaap.com/chainrxn/, since I had liked it a lot. Another reason was to familiarize myself with testing suites in AS3.0, and using Facebook's Graph API.
For the ease of measuring progress, I have divided the work in four simple steps.
Introduction to important AS3.0 concepts (how function overloading works, stage, maintaining layers in stage, fluid layout)
Using external libraries, frameworks (puremvc, collisiondetectionkit)
Unit tests, regression tests
Publish the app on Facebook, and use facebook's Graph API