Google Glass team recently unveiled the Glass Development Kit (GDK) without a 'Hello World' sample project. This project helps fill that gap.
The project is pretty straightforward. If you've done Android development before, all you'll have to do is download Android SDK v4.0.3 (API 15) along with the Google GDK Sneak Peak that is available inside that bundle. Open the project in IntelliJ and run on your Glass.
You should see something like this:
Feel free to contribute to the project and make it better if you like! :)