Q:

What languages do date, time, and calendar operations really well?

This is probably too much to ask, but is there any language that does a really terrific job of representing time and date operations?  I'll grant straight away that it's really hard to write a truly great time library.  That said, are there any widespread languages that have one?  Basically, I want something that handles time and date as comprehensively as modern regular expression libraries do their jobs. Everything I've seen so far in Python and Java omits one or more pretty important pieces, or makes too many things hard.
At least this should be intuitive to do:

find the number of days between two given dates, number of minutes between two given minute periods, etc.  
add and subtract intervals from timestamps  
allow simple conversion between timezones, with Daylight Saving Time changes by region automatically accounted for (given that there's an accurate supporting database of regional settings available)  
get the period that a given timestamp falls into, given period granularity ("what calendar day is this date in?")  
support very general string-to-date conversions (given a pattern)

Further, if there's a Java-style Calendar/GregorianCalendar setup, the general Calendar class should be accommodating toward subclasses if I need to roll my own Hebrew, Babylonian, Tolkien, or MartianCalendar. (Java Calendars make this pointlessly hard, for example.)
I am completely language-agnostic here.  It's fine if the thing chokes on computing ambiguous stuff like "how many minutes are there between 2002 and next Valentine's Day?"

A:

How about .NET's DateTime? (You can pick your language within the framework)

A:

Are you looking for something like PHPs strtotime? That will give you the unix timestamp of almost anything you can throw at it. 
From the php site:
<?php
echo strtotime("now"), "\n";
echo strtotime("10 September 2000"), "\n";
echo strtotime("+1 day"), "\n";
echo strtotime("+1 week"), "\n";
echo strtotime("+1 week 2 days 4 hours 2 seconds"), "\n";
echo strtotime("next Thursday"), "\n";
echo strtotime("last Monday"), "\n";
?>

.NET's date classes require much more arcane fiddling with DateTimeFormatInfo and the like to parse date strings that aren't nearly as complicated as strtotime can handle.
PHP provides a DateTime class and a DateTimeZone class as of PHP 5, but they're both quite poorly documented. I still mostly use unix timestamps and the date, time and strtotime functions as I haven't fully come to grips with the new objects.
The following links attempt to flesh out DateTime and DateTimeZone a bit better:

http://laughingmeme.org/2007/02/27/
http://maetl.coretxt.net.nz/datetime-in-php

A:

For Java, I highly recommend the Joda Date/Time library.

