Sounds like she's doing a guitar arrangement of "Porge Amour" from Le Nozze de Figaro (possibly the silliest opera ever written.) Before, it was "The Black Swan", from an opera called The Medium. It's one of the flat-out spookiest pieces of music I've ever heard -- think William Hope Hodgson does opera.
Now she's done a segue from "Porge Amour" to "April Come She Will".
Sometimes, I wonder why I got married. Other times, I know.