dhtmlx Scheduler - Light weight and fast, this fully javascript calendar provides a rich solution for scheduling. Advanced AJAX functionality allows drag and drop changes to scheduling as well as editing, updates, additions and deletion with no page refreshes. This script is the front end only requiring either the dhtmlx Connector or your own code to integrate the calender with a server database. Formats, language and even a Skin Builder give many customization options. dhtmlx also offers this calendar as a module for Joomla and Drupal.