Is there a way to export an entire sharepoint site so that in the event that sharepoint is unavailable for a day, the site and its contents are viewable/accessible? Something along the lines of 'Export to HTML'?!? Even if it is not possible with the entire site, would it be possible to export a wiki? This would be beneficial to us as we rely on information stored in this wiki day-to-day.

no this is not possible. What you can do is take backups and restore it on other web application or other Web Front server. Thanks, Ketan