Ken Jennings has been named the "first interim guest host" of Jeopardy! Article says there will be a series of guest hosts (none besides Jennings identified to date) and that no long-term replacement host will be named at this time. His shows begin airing January 11.
Ken Jennings went to the school I attended in Seoul. Deslok taught there - well after I was there and after Ken Jennings, too.