I have not yet been given an actual cause for this nearly week long outage, but after spending hours on the phone with the host company today, repeatedly reminding them that they had assured the site would be back up before this past
weekend, here we are back up and running... finally!
Not sure how long the forum was down, but it was caused by a PHP error on the server.
And a thanks goes out to @adamzan for bringing it to my attention.