WP FullCalendar

FullCalendar is a free open source jQuery plugin which generates calendar populated with your events, posts or any other custom post type. This plug-in combines FullCalendar and WordPress to present posts in a calendar format, which can be filtered by custom taxonomies such as categories and tags. Features include AJAX powered, month, week, or day views, style your calendar with themes or create your own with the jQuery ThemeRoller, filter by taxonomy such as category or tag, supports custom post types and custom taxonomies, popout post summaries and thumbnails when you hover over your calendar items using jQuery qTips, and various hooks and filters for added flexibility.

Requirements:

WordPress 3.3 - 3.4.1