I have a site where I would like to display past events in reverse chronological order.

For example, see this page:
http://www.tiredwired.com/modules/piCal/index.php?&smode=List&num=20&cid=0&order=...

Which finds and shows 20 events (per page) before today's date.

By default the page shows events in normal chronological order (oldest to newest).

How can I code the URL parameters to change the order of display so that the newest (most recent events) show up first?

I tried order=end but that did not do it.