We happened on a small theater which presented Opera Arias and Neopolitan Songs in a small theater near the Pantheon. The performance starts at 7:30 pm and runs a little over an hour. The performance was wondefful and they got several ovations. You can not get a bad seat in this theater. It is in a old church building on Piazza Santa Chiara. Google Opera Arias in Rome and you will get the web site. Tickets were 40 Euros, but the cheaper seats would have been just as good. There is a small bar in the theater that serves drinks beginning at 6;30 PM.