MAKE Flickr pool member shklaw found an old voltmeter in the trash and made it into this awesome Nixie tube clock.
These Nixie tubes are NL-5440A’s. The banana sockets were replaced with switches to set the hours and minutes. When the rotary switch on the left is set to OP, the clock is off, when it it’s set to AC, the clock is on (but can’t be set) and when the switch is set to DC, the clock it still on and you can set the time using the push buttons. The ohms adjust dial on the right controls the brightness of the blue up-lighting (fully off to quite bright!). I used the schematic and PIC code from this site.