Once you've clicked on a column header of a sortable table, there's no way to bring back the original order other than to reload the page. This is frustrating. I've refreshed the page numerous times just to see the original state, and so have many people I imagine, which means we're wasting traffic (I know it's infinitesimal in the grand scheme of things, but still).
I suggest we make a third click on a column header reset the order of the table, as demonstrated on this page (h/t Xaosflux). Apparently both the fork on that page and our tablesorter are based on the same plugin, so I suspect it wouldn't be difficult.