From the German based lab Interactive Minds provides the EyeMusic interface which lets you play songs. Not much information is available except the screenshot below.
However, their eye tracker "EyeFollower" seems more impressive. 120Hz sampling and 0.45 deg. accuracy. Furthermore, it allows for larger and faster head movements than most other remote based systems. This is really important for making the tracking flexible, which is what you want with a remote based system in the first place. People move around, we all change posture over time. Imagine sitting at a desk then turning to the side taking notes, talking on the phone. When you return to the computer it should instantaneously continue to track your gaze without any noticeable delay (or having to re-calibrate) These are not easy tasks to solve but are necessary for the advancement of eye tracking/gaze interaction. Interactive Minds provides a demonstration video of their EyeFollower. Looks great.