Some time ago I participated in first Google Glass Hackathon in Poland, where I had possibility to test Google Glass, try it and write applications, which can be run on this cutting-edge device.
It was very interesting experience. In addition, I took 2nd place with my team, what made me happy after leaving Warsaw late night.
In a few hours, we created simple native application for Android platform, which can be used as a city guide with augmented reality, geolocation and image recognition. We called it Hereandhounds. You can see its source code at:

You can read detailed report from that event at technical blog of Future Processing: Unfortunately, its available only in Polish language right now.