I remember having a bit of fun computing the number of work hours between two dates. It involved: - the day of the week (office closed on weekends) - day of

I remember having a bit of fun computing the number of work hours between two dates. It involved: - the day of the week (office closed on weekends) - day of the year, with leap years (office closed during holidays) - Easter day (some holidays are based on Easter) - DST and timezones (office hours are in local time, timestamps are UTC) Thankfully, no Julian calendar or leap seconds to deal with.