I needed to know, so I wrote one of those trendy single page apps: is LOST on yet?. Naturally, the source is on github. It’s really pretty amazing actually:

def is_lost_on_yet?
  @is_lost_on_yet ||= {:answer => "no", :reason => "returns on Jan 21st, 9PM ET"}
end

I have about 20 days to finish the site :)

Update: I forgot to mention, it even has JSON support!