He just randomly did "So long, Farewell!" at the end of his segment at DAVID LETTERMAN and to conclude his performance, four children dressed in SOUND OF MUSIC attire came out for the final "goodbyes."
HILARIOUS! Very unexpected and twas a good laugh.
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle