Edit: here's a video of it running (somehow the seconds hand runs backwards)
> This clock is inspired by a post by ILAMtitan on the 43oh.com forums, which was in turn inspired by Vetinari's clock from the Discworld series of novels. Although the movement of the second hand is quite erratic, it ticks exactly 32 times in 32 seconds, and so keeps quite accurate time overall. The clock started life as a cheap $3 clock from KMart. It's mechanism was kept, but the driver circuit was removed and replaced with an MSP430 microcontroller. ILAMtitan's code is designed to ensure that every 32 seconds it will tick 32 times, but the exact timing of those 32 ticks is variable. There can be as little as 1/4 second between ticks or as much as 24 seconds. Overall though it will keep quite accurate time.
I will have to buy some cheap clocks and start tinkering.