Tchaikovsky's operatic version of Alexander Pushkin's Queen of Spade isn't one of my favorite operas... Though I can be persuaded to sit through the whole darkly creepy work just to catch the couple of minutes that this little Act II duettino between Lisa and Pauline charms the stage.
Especially when Lisa is sung by one Edita Gruberova and Pauline one Vesselina Kasarova! Gosh... I hope they get together for another run of joint recitals before Gruberova retires in 2012! One is a very high soprano (known for her high G's in the alt while singing things like Zerbinetta or Lucia di Lammermoor or Gilda in Rigoletto or Donizetti's 3 Tudor queens), and the other is a true mezzo-soprano with lustrously dark chest notes... and yet both their voices and personalities blend so well it's almost like hearing the same soul in a tuneful conversation with itself.