Here is a cool 4 digit numitron clock based off of what appears to be an ardunio. Based on the GitHub description:
DecadeCounter.com posted this video of their single digit numitron clock, the YS-950, powering an end-view numitron. Check it out:
DecadeCounter.com / the Vintage Technology Association has a great new gadget for sale - it is (what I believe to be the only) single tube numitron clock for sale. And best of all, you can't beat the price: $24.98 for a kit or $31.98 for a fully assembled and working version. All you have to do is supply 5VDC and you're in business. (For the record, USB ports put out 5VDC.)
The display has two parts to it - the numitron tube and 4 LEDs. The LEDs indicate what position is being shown (HHMM). The actual timebase is provided by a quartz crystal. One of the unique and cool features of this clock is that you can actually correct the time base to accommodate for changes in temperature, aging, etc. There is a coarse adjustment that adjusts in 2 second increments and a fine adjustment accomplished by adjusting a capacitor with a flat head screwdriver. The entire gadget is powered by 16F628 PIC microcontroller.
If you're looking for a stocking stuffer for Christmas or need a nice little gift, this is the one to get.
There are two things I like about this design: it is small and it has a black PCB. It is hard to emphases just how small this actually is - it is only about twice the length of the PIC microcontroller! This device is small and easy to mount. Just supply a modified USB cable for power and you can put this guy just about anywhere. I know it seems trivial, but compared to my NixiChron, this little thing is portable. Of course, the exposed black PCB will make all of your nerd friends jealous.

Many more photos after the Read More link

DecadeCounter.com has a new kit and clock for sale on their website - it is a single digit numitron clock. I really like the small design of the kit and you can't go wrong with the price. Check it out. Lastly, check out Accutron's post on the forum if you have any questions.
The YS-950 is an inexpensive single-digit clock equipped with a 'Numitron'-style seven-segment filament display tube and a 16F628 PIC microcontroller. The YS-950 displays time by cycling through each digit incrementally, starting with the tens of hours position and ending with the minutes position. A row of four LEDs along the side of the device indicate which digit is currently displayed. The display will remain idle for a user-defined amount of time between each digit display cycle.