PDFs -- Download monthly calendars as PDF
InconstantMoon -- An easy to read description of many things to do with the moon. Blue moons, phases, etc.
TodayDate -- Today's date and time, in pretty much every calender ever invented. Lots of links to reference information on these calendars
Google -- Google's calendar links
WorldTimeZone -- Find the time in any time-zone (warning: advertisement-central)
NetTime -- A program which will synchronise your computer to various atomic clocks around the world
Trove -- Wolfram's calendar area
EasterDate -- Methods for calculating the date of Easter (includes sample programs)
TimeZones -- Information and databases on timezones around the world
