I am occasionally away from my time machine disk. During these periods I would still like to backup my calendar in case the hard disk (MacBook's) crashes.
Which file or directory should I copy to backup iCal's entries?
Edit
I am looking for a maintenance-free backup method (i.e. one that does not require me to think about it until something bad happens).
Might it be possible to sync iCal with a cloud-based (perhaps Google's) calendar? Is it possible afterwards to sync back into iCal?