When Apple went from the ginormous original Apple TV to the minuscule black plastic box that is the second model, a lot of owners of the first-generation unit were suddenly asking themselves what to do with the aluminum and plastic slab. While we've seen the original Apple TV transformed into a regular clock, designers at Atelier Kurth had a better idea: using Nixie tubes to create a "proto-digital clock."
Nixie tubes were the vacuum tube equivalent of today's segmented LED displays. They were used in many early electronic devices, including calculators, to display numbers. Nixies give any electronic a certain Cold War chic, and the warm, flickering glow of the tubes is both nostalgic and disturbing in a "Brazil" way.
Atelier Kurth's ATV1 clock uses six Nixies to display the time, with the first column of numbers showing the hour, the second minutes, and the third seconds. Core77's blog entry on the clock mentions that the tubes have an expected lifetime of 200,000 hours (almost 23 years) and that there are 108 connections behind the Apple faceplate.
The clock falls back on the design of an earlier clock from Atelier Kurth that used a concrete block as a base. A video showing that predecessor Nixie clock is seen below.