Not sure if it qualifies as under-rated, but there is a night tour of the Roman forums with what's basically a documentary about roman life projected on the ruins, highlighting details and providing context. I found it great (also because it's been produced- and narrated, in the Italian version- by Piero Angela, a beloved science documentarist that has interested in science entire generations of Italians, sort of an Italian David Attenborough). I was there with a friend who's a native English speaker and she enjoyed it a lot as well.
http://www.viaggioneifori.it/en/