FullCalendar is a jQuery plugin that provides a full-sized, drag & drop calendar. It uses AJAX to fetch events on-the-fly for each month and is easily configured to use your own feed format (an extension is provided for Google Calendar). It is visually customizable and exposes hooks for user-triggered events (like clicking or dragging an event).

FullCalendar is great for displaying events, but it isn’t a complete solution for event content-management. Beyond dragging an event to a different day, you cannot change an event’s name, time-of-day, or other associated data. It is up to you to add this functionality through FullCalendar’s event hooks.

Requirements: jQuery and jQuery UI Framework
Demo: http://arshaw.com/fullcalendar/
License: MIT, GPL License