The Holiday Calendar (the-holiday-calendar) free WordPress plugin

This calendar comes as a widget that shows your upcoming events. If you want you can automatically import the holidays from http://www.theholidaycalendar.com.

Two views are available: calendar view and list view.

If you choose to import the holidays they are fetched from a webservice. This happens asynchronous so your website will not get slow.

For more information about the webservice visit: http://www.mva7.nl/the-holiday-calendar-webservice-manual.html