I think that a good development for your project would be to build a very simple radio reciever which can receive the time code signals sent by longwave on 70Khz and interface that to your clock,use the micro to decode the msn signals and then your clock would be syncronised to the world time standard.So thats a bit of code to decode the signal from the receievrand youve got a very cool clock which is accurate to +/- 10^-9 seconds a year.
The radio is very simple Ive got a schematic for it somewhere if I can findit.