Once More, With Vengeance
“So, I've got this question,” Tony says when he walks into the Avengers' living room this morning, “and feel free to ignore me if, y'know, I'm talking crazy here, but have any of you spontaneously burst into song lately?”
There is a moment of total silence. Then Natasha curses in Russian and Clint bursts out with “I knew there was something off with those back-up singers!” Steve says nothing, but he blushes, and Thor claims that he noticed nothing out of the ordinary, as he tends to spontaneously burst into song anyway.
Or, the one where New York falls under a musical spell and that is not nearly as much fun as it sounds like.