Using his one of his Grandfather's broken old pocket watches as a starting point, one modder [Paul Pounds] skilled in the ways of microelectronics replaced the face with a system of 133 hand soldered LEDs.
Starting from scratch, he designed a PCB complete with 133 (hand soldered) LEDs, room for a temperature controlled oscillator for real time clock capabilities, a LiPo battery, and a cell phone vibrator to provide a simulated "second hand tick" feeling. The whole watch is powered by a PIC 16F946.
You would think that improving on such a beautiful design would be difficult, but a second version is already in the works that will feature a "more compact, lower power TCXO, automatic NTP syncing, and a USB port for charging and reprogramming". Check out Paul's website for more information on how to build one yourself. [Project Page via Hack a Day via Geeky Gadgets]