We'll create fresh WordPress site with The Holiday Calendar installed. You have 20 minutes to test the plugin after that site we'll be deleted.
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