QuickGlass is a simple web application I built to make it very easy to develop custom commands for Glass.
Basically, you choose a trigger word (something to say after "Okay Glass...") and provide an HTML page for it to load. This can redirect to other pages or make AJAX requests, etc.
There are some examples in the examples folder.
You can access the live version and build your own APKs here.
This will build an APK that you can sideload. If you're not sure how to do that, Google "sideload APK google glass". There are many guides that are very good.