Well, here's a design we've instantly fallen in love with. It's the Monochron, a Pong-playing clock by engineer and retronaut Limor Fried of Adafruit Industries. The Monochron comes as a kit you put together yourself, and after some simple soldering and a little toolin', you'll have yourself a white-on-black retro gaming classic reborn as a clock.
The Monochron keeps things simple, displaying the time in either 12-hour or 24-hour formats, gives you an alarm function with snooze, and has a backup battery in case things go south. It's also just one pretty damn charming presentation, as the time rolls forward a minute each time one of the paddle misses the ball (which, of course, happens once a minute).
It's worth noting that if you've got a big of programming know-how, the Monochron is an open platform and hacking is encouraged.
See it in action in the video below.