I hop around re-watching particular episodes as I please, so the last one (at the moment) is VOY S03x08 and 09 - "Future's End".
(I only watched it because I was looking for a description of what an Intrepid-class torpedo bay would have looked like, and the Chakoteya Trek screenplay repository suggested that Janeway went down to manually launch a torp - a very purposeful intention on my part)