This is an effort to figure out how to best markup the operating hours (workhours, hours open, etc.) of venues (stores, restaurants, museums, offices, and other establishments) that have set hours and are open on a regular basis.
Per the The microformats process
Operating Hours Brainstorming
This should be moved to opening hours brainstorming.
This section documents a method that can be used to mark up the operating hours of stores, restaurants, museums, offices, and other establishments that have set hours and are open on a regular basis. This is based on the hCalendar 1.0 microformat.
This effort came about as a result of the need for a human and machine readable markup format that can be used to define the operating hours of establishments.
Stores, businesses, etc. often provide their operating hours on their websites. With the addition of a small bit of markup, they are able to define their operating hours on their websites in such a way that spiders and other aggregators can retrieve such hours, automatically convert them to the iCalendar format, and use this data in any iCalendar application or service.
Using RRULE in hCalendar
This was suggested  by Brian. Is this the most appropriate method? --Nick
// example definition of operating hours using RRULE in hCalendar <h1>Pardon the Interruption</h1> <p class="vevent"> <a class="url uid summary" href="http://sports.espn.go.com/...">Pardon the Interruption</a> is a <span class="category">TV</span> <span class="category">sports</span> show. <abbr class="dtstart" title="2001-10-22">It airs</abbr> <span class="rrule"> <span class="freq">weekly</span> <abbr class="byday" title="mo,tu,we,th,fr">Monday to Friday</abbr> at <abbr class="byhour" title="5">5:30pm</abbr> </span> <!-- timezones should be avoided --> <abbr class="tzid" title="US-Eastern">ET</abbr> on ESPN. The hosts of the show are longtime friends <span class="hcard"> <span class="fn n"> <span class="given-name">Tony</span> <span class="family-name">Kornheiser</span> </span> </span> and ... (hCard for Michael Wilbon not shown) <span class="description">They discuss - and frequently argue over - the top stories of the day in "sports... and other stuff".</span> </p>