I see that Rufus Wainwright's new project (see Gillian Martin's post below) even gets a mentions on the Current's blog -- nothing like a new opera to light up the blogosphere.
According to the New York Times article that Gillian links to, Wainwright's "Greek Song" makes a sly reference to the opera Der Freischutz.
But I'm not so sure; I wonder if there was a slip somewhere along the way. To me, it sounds like a different opera, Mascagni's L'Amico Fritz. Here's a clip of each, so see what you think; go about 1:10 into the opera scene to get the Big Tune.