If you combine Ian's adventure into the world of Nixie tubes with my freeformed Litte Wire clone you get something like this:
It's a clock made of a single IN-1 Nixie tube controlled by a ATMega8. The Mega8 directly controls 10 pcs of MPSA42 high voltage transistors for lighting up the filaments in in Nixie. It also generates the high voltage required for the tubes by a pwm output connected to a IRF520 N-FET and the usual inductor and fast recovery diode.
Unfortunately I've lost the schematics and firmware many years ago...
Here's a link to a youtube movie showing the clock in action.http://youtu.be/06-RMMxYA1Q?hd=1