The Nixie Tube was, in a more enlightened era, the standard method for electonically displaying numbers, letters or other symbols prior to the introduction of the LED. Those of you of a certain age will remember that all calculators once utilized Nixies.
According to Wikipedia:
The Nixie display was developed by a small vacuum tube manufacturer called Haydu Brothers Laboratories, and introduced in 1954 by Burroughs Corporation, who purchased Haydu and owned the name Nixie as a trademark. The name Nixie was derived by Burroughs from "NIX I", an abbreviation of "Numeric Indicator eXperimental No. 1". Similar devices that functioned in the same way were patented in the 1920s, and the first mass-produced display tubes were introduced in the late 1930s by National Union Co. and Telefunken. However, their construction was cruder, and they failed to find many applications until digital electronics reached a suitable level of development in the 1950s.
Burroughs even had another Haydu tube that could operate as a digital counter and directly drive a Nixie tube for display. This was called a "Trochotron", in later form known as the "Beam-X Switch" counter tube; another name was "magnetron beam-switching tube", referring to their similarity to a cavity magnetron. Trochotrons were used in the UNIVAC 1101 computer, as well as in clocks and frequency counters...
Citing dissatisfaction with the aesthetics of modern digital displays and a nostalgic fondness for the styling of obsolete technology, significant numbers of electronics enthusiasts in recent years have shown interest in reviving nixies. Unsold tubes that have been sitting in warehouses for decades are being brought out and used, the most common application being in homemade digital clocks. This is somewhat ironic, since during their heyday, nixies were generally considered too expensive for use in mass-market consumer goods such as clocks. This recent surge in demand has caused prices to increase significantly, particularly for large tubes. The largest type known to be in the hands of collectors, the Rodan CD-47/GR-414 (220 mm [8.7 in.] tall), have been sold for hundreds of dollars apiece, but these are extremely rare and only found in a few areas of the world by persistent and fortunate seekers.
David Forbes and his homebrew electronics company, Cathode Corner, often have marvelous examples of Nixie-powered clocks and wristwatches for sale on their site and on eBay.
Curious about jumping into the wonderful world of Nixies yourself? Go to the Sphere Research Corporation for all your Nixie needs.