Numitrons are neat display devices similar to nixie tubes but designed for much lower voltages. Numitrons are basically incandescent displays in which filaments create the segments.
They have a retro look that i liked so much. I bought 6x IV-9 russian numitrons in ebay, they were about 3$ each, they're pretty cheap!
At that time i didn't know what to do with them, but then i thought about a clock. Using software from a single LED display clock i made this impressive numitron clock.
Step 1: Program the PIC
The original purpose of the software was to drive a single common-anode LED display rather than a numitron, but either way works.
The software was modified to flash the digits so the HHMM LEDs wouldn't be necessary. Also the software was modified so if the tens of hours is 0 then it is not displayed.
Moreover, the software does not check the input values so entering the wrong time such as 67:85 would be accepted, but eventually the clock will start resetting the digits correctly.
The clock operates off a PIC 16F84A using a program written by David Tait (software is further down this page). The crystal oscillator for the clock is a 4MHz crystal.
I think another microcontroller such as PIC16F628A could also work fine.