I modified an old Heathkit clock, adding a microcontroller to it that would get time from a GPS receiver, and set the Heathkit's time after a power outage. It also restore the alarm clock setting, makes switching to and from Daylight Saving Time easier, and synchronizes the clock to the second, every midnight. For more information, see http://www.galacticstudios.org/heathkit-clock-hack/
