The Cylon Nest
Now with support for the Nest Thermostat, Cylon.js is coming to a smart home near you. Two Nest-related drivers are currently supported, nest-thermostat and nest-home. The nest-home driver can be used with Cylon to interact with the Nest through an Arduino's LED's and buttons, letting you interact with your home through your robots!
As a fun weekend DIY project, you can hook up an Arduino so that a couple of LEDs tell you the away status of the Nest in your home, and pressing a button tells your Nest to change that status. Check out the code to make it happen in the article "The Cylon Nest" on the Cylon.js blog.