I saw this:
...but the link just pointed to the chat room, where I couldn't find any relevant explanation. In fact, the only thing containing "thon" that came up using "find" was a link to an old post about an answer-a-thon. I never really got the hang of chat rooms...
I couldn't find anything on meta, either, which is where I'd expect such a thing to be announced or discussed.
What's it all about?
I hope the idea isn't to artificially game the "questions answered" stats by closing on-topic but challenging older questions, just because no-one has answered them yet? A travel site having difficult questions that can't be solved using Google alone is healthy.