This is one of the clocks I am working on, and it is very cool but a bit of a challenge.

I'll try to capture and post some good video of it in action, but for now I'll post the STL and if anyone is interested, just PM me, and I'll send out the arduino programming...

Here is the 72x LED Charlieplexing wiring diagram.  36 pairs of opposite polarity LEDS, controlled by only 9 pins.

I call it the Eclipse Clock, because it looks like an Eclipse, with dark spots (or light spots depending on how you set it) outside  the ring to represent the hours, minutes, and seconds...

it uses 3mm LEDs, an Arduino or clone, a Real-Time-Clock module (chronodot), and a WHOLE LOT OF SOLDERING!

I'd love it if someone else would try building one of these.  I'll help out in almost any way i can!