I'd suggest having a look at the Goid Relations ontology http://wiki.goodrelations-vocabulary.org/Quickstart - it's aimed at businesses but the OpeningHours specification might do what you need http://www.heppnetz.de/ontologies/goodrelations/v1.html#OpeningHoursSpecification

While handling public holidays etc is not immediately obvious it is covered in this mail http://ebusiness-unibw.org/pipermail/goodrelations/2010-October/000261.html

Picking up on the previous comment Good Relations in RDFa is one of the formats Google use for Rich Snippets and it is also picked up by Yahoo

Owen

On 7 Jun 2011, at 23:05, Tom Keays <[log in to unmask]> wrote:

> There was a time, about 5 years ago, when I assumed that microformats
> were the way to go and spent a bit of time looking at hCalendar for
> representing iCalendar-formatted event information.
> 
> http://microformats.org/wiki/hcalendar
> 
> Not long after that, there was a lot of talk about RDF and RDFa for
> this same purpose. Now I was confused as to whether to change my
> strategy or not, but RDF Calendar seemed to be a good idea. The latter
> also was nice because it could be used to syndicate event information
> via RSS.
> 
> http://pemberton-vandf.blogspot.com/2008/06/how-to-do-hcalendar-in-rdfa.html
> http://www.w3.org/TR/rdfcal/
> 
> These days it seems to be all about HTML5 microdata, especially
> because of Rich Snippets and Google's support for this approach.
> 
> http://html5doctor.com/microdata/#microdata-action
> 
> All three approaches allow you to embed iCalendar formatted event
> information on a web page. All three of them do it differently. I'm
> even more confused now than I was 5 years ago. This should not be this
> hard, yet there is still no definitive way to deploy this information
> and preserve the semantics of the event information. Part of this may
> be because the iCalendar format, although widely used, is itself
> insufficient.
> 
> Tom