Determining actual elapsed (wall-clock) time

[flamesrock]

I've needed to do something similar in the past and used free ntp
servers. Of course you need an internet connection:
http://ntp.isc.org/bin/view/Servers/NTPPoolServers
http://www.nightsong.com/phr/python/setclock.py

You could also have a startup script spawn a thread that stores the
time persistently in a shelf object, sleeps for a minute, and checks to
see if the current clock time is greater than a minute (+/-sec,) and
subtracts the difference. Or even check it against an NTP server if you
can.