Hi Keith,
If you can point out some sources whch can be accessed in a manageable way, then maybe this is achievable. The solution needs to be maintainable into the long term, therefore I suggest this need to be obtianed from a long term reliable source (maybe from the OS if that is available). Regular updates via Events module install is not an appropriate mechanism, since potentially somebody could be using a version of the module released now in 2/3/4 years time. In which time holiday dates will undoubtedly have changed.
Using the mechanism I have described in my post, you would have to enter the holidays once. In the UK there is about 10 days holiday, therefore 10 events. This may help you solve your problem for now, since a version of the events module with the capability you requested may be some months away.
In any case, can you raise this on Gemini - http://support.dotnetnuke.com, so we can track for inclusion in a future release?
Thanks
Roger