Leonardo Da Vinci supposedly kept a polyphasic sleep schedule - that means that he took 30-minute naps after each 3.5 hours - and that might've been the secret behind his productivity. This concept clock could help you do the same.
Basically the clock won't ever show you a time. Instead it will tell you if you should be awake or if you should be going to sleep. That's it. Of course it's up to you to actually obey the gadget's commands. [Yanko Design via Unplggd]