There is a website in Finland which offers free online holiday calendars for many countries. This is very useful especially for European countries, where the time group module cannot calculate certain holidays.
goto
choose your country on the left, adjust the calendar settings and click on the download link. Copy the downloadlink, remove ‘webcal:’ at the beginning and replace it with http://
For the Austrian holiday calendar it looks like this
These online calendars autoupdate every year…