I’ve a ‘real’ nixie clock, and another (pictured) that’s inspired by Nixie clocks. A Nixie Clock uses 6 Nixie tubes to display the time. These tubes use neon technology and have the ten digits all layered behind one another inside the tube. This means that the clock has internal high voltage, but it uses digital technology to keep time. The Mike’s Electric Stuff blog has plenty of information about these.
I also have a ‘nixie-inspired’ clock, which came as a kit from China and displays the time on blue LED 7-segment displays. Here’s a picture of it; I think it looks pretty cool. One of its features, taken from ‘real’ nixie clocks is that as the digits change, they cycle through 0 – 9 first: It also spells out ‘HELLO’ when you turn the display on and ‘SEE YOU’ when you turn it off.
