If you're a Linux user and work on the command line and care about church calendars . . . well, perhaps you've missed this as long as I have.
To find the date of Easter for a particular year according to the Western churches, say 2009 type:
$ ncal -e 2009
For the Eastern churches, type:
$ ncal -o 2009
Those are both in April.Â To get a quick calendar, type
$ cal 4 2009
ncal 4 2009
for a different arrangement]
There are other handy helps:
for instance gives the date where calendars changed from the Julian to the Gregorian in several countries.