Nearly a decade ago, I got the idea that it would be really cool to build a clock out of those little glowing tubes used to disply numbers on electronic cash registers before LEDs came along. There was one tube per digit, with a separate fillament in the shape of each number, and they would glow neon orange. I asked around on USENET and learned that they were called Nixie tubes. Of course, I never actually built a clock with one.
Appearanlty I wasn’t the only one with the idea, because several people have built nixie clocks. There is even
an article on it in IEEE Spectrum with a brief history of the device and photos of various tinkerers completed clocks. Even better, this guy’s site has plans for one (as well as lots of other cool electronic and electrical artifacts and experiments). One fellow even made a nixie wristwatch.
There are also people selling completed clocks, but I’m not about to send my large and affluent readership their way without compensation, so you folks will just have to search on google yourselves until my people can work out some sort of paid placement deal.