A calendar written in PHP5 I've developed as a side project.
Runs in E_STRICT without throwing errors.
Has support for international date formats.
Able to start on any day of the week.
Lots on configuration possibilities through CSS.
Example code available here: http://blog.152.org/2010/10/php-bcalendar-my-take-on-php-calendar.html
Documentation available here: http://files.152.org/php/bCalendar/docs/
Demo available here: http://152.org/cal.php
There is also documentation located in the docs folder.

TODO  
- Turn into a JSON feed that can be imported through javascript and written to the page