Here is a site that launched a page for an upcoming event. This event got very popular in the niche and a lot of heavy-weight sites voluntarily linked to it. As a webmaster, I couldn't be happier.
Subsequently Google adjusted its ranks such that relevancy of other pages were ingnored, including the homepage, in favor of this page for queries this events page doesn't give answers to. Naturally the bounce rate increased and conversions reduced. The event is over and the page lived its life. It debunks the theory however that Google returns the most relevant page from your site, no matter what their individual popularity is.
The most prudent thing to do, IMHO, is to 301 redirect this page to the homepage. One might even be tempted to redo the page so that it becomes relevant to many of the queries this page ranks for and let it remain 200. Which is the diligent thing to do?