Ajax Event Calendar is a wonderful free wordpress plugin to easily add and manage events in your WordPress blogs. It is fully localized and authorized users can add and edit events in a single click. You can display the events by a calendar view or as a list of events or by both.

Plugin URL:http://wordpress.org/extend/plugins/ajax-event-calendar/
FAQ:https://code.google.com/p/wp-aec/wiki/FrequentlyAskedQuestions