Probably clocks got most attention from embedded hobbyists. This one is pretty interesting and unusual as it is based on three analog multimeters. One is dedicated to display hours, another minutes and third seconds.
Multimeters are driven by PIC 16F628A microcontroller which also tracks time internally. Anyway clock is well designed there would be no problem to hang it on the wall.
Embedds highly recommends EasyEDA for circuit and PCB design