Just a day before the open evening at school were I plan to demonstrate the Lego Clock, a short circuit damages the real time clock's crystal and prevents it from keeping time.  Luckily this old timer comes to the rescue:
With the knowledge that most timer/clocks use a standard 32.768kHz crystal I robbed the oscillator from this timer and swapped out the faulty one on the RTC, to may amazement my fix worked and everything was back on track.