Trax posted his nixie tube clock on Elektronika.ba. He used 4 tubes to show the time, the date and the temperature. But it looks like that he was not still 100% pleased with the look and feel of the nixie tubes, so he added 4 RGB LEDs beneath them to make their bases glow. The LEDs are controlled with the TLC59401 16-channel LED driver from Texas Instruments. He used the power booster from the Ice Tube clock. The brains is the AVR ATmega32 with a typical 32.768 kHz external crystal for time keeping. More info can be found here.