Scattered Thoughts

The next most popular microformat is the hCalendar (HTML iCalendar). This is used to create events/ entries in calendars based on the iCalendar standard.
Now an upcoming event for me could be mentioned as follows

Citizenship Ceremony - 6th September

To convert this to an hCalendar microformat we have to remember that the dtstart and summary fields are required fields.

The dtstart to mention the start date and the summary to write what the event is about, the rest are all optional.
The dtstart field must follow the following standard (YYYYMMDDTHHMMSS+ZZ:ZZ). Here is what the event would look like after we added in the two required fields:

<div class="vevent" id="hcalendar-Citizenship-Ceremony">
  <abbr class="dtstart" title="20070906T1845+1000">September 6th 6:45pm</abbr>,
  <span class="summary">Citizenship Ceremony</span>— at
</div>

We can then go and add the following classes as well

• dtend : the date the event is meant to end

  <div class="vevent" id="hcalendar-Citizenship-Ceremony">
    <abbr class="dtstart" title="20070906T1845+1000">September 6th 6:45pm</abbr>,
    <abbr class="dtend" title="20070907T2000+1000"> 8pm 2007</abbr> —
    <span class="summary">Citizenship Ceremony</span>
  </div>

• description: describes what the event is about

  <div class="vevent" id="hcalendar-Citizenship-Ceremony">
    <abbr class="dtstart" title="20070906T1845+1000">September 6th 6:45pm</abbr>,
    <abbr class="dtend" title="20070907T2000+1000"> 8pm 2007</abbr> —
    <span class="summary">Citizenship Ceremony</span>—
    <div class="description">My citizenship ceremony</div>
  </div>

• location: where the event is to be held

  <div class="vevent" id="hcalendar-Citizenship-Ceremony">
    <abbr class="dtstart" title="20070906T1845+1000">September 6th 6:45pm</abbr>,
    <abbr class="dtend" title="20070907T2000+1000"> 8pm 2007</abbr> —
    <span class="summary">Citizenship Ceremony</span>— at
    <span class="location">Australia</span>
    <div class="description">My citizenship ceremony</div>
  </div>

• url: webpage relates to the event

  <div class="vevent" id="hcalendar-Citizenship-Ceremony">
    <abbr class="dtstart" title="20070906T1845+1000">September 6th 6:45pm</abbr>,
    <abbr class="dtend" title="20070907T2000+1000"> 8pm 2007</abbr> —
    <a href="http://eventsite.com" class="summary url">Citizenship Ceremony</a>— at
    <span class="location">Australia</span>
    <div class="description">My citizenship ceremony</div>
  </div>

This is what we finally have and what the event will look like when entered into a page (minus the url addition)

Read more about the hcalendar microformat here:

microformats hCalendar wiki
hCalendar Cheatsheet