This could be considered to be a novelty although it stands on its own as a serious concert piece. It's Ravel's Piano Concerto for the Left Hand http://www.youtube.com/watch?v=cGOWZ7nNZFM&feature=related
It was commissioned by Paul Wittgenstein, an Austrian virtuoso pianist, who lost his right arm in WWI.
It gets to 2:25 on the track before the piano comes in. It's a complex piece and it is said that some two handed pianists do in fact cheat, although there is no sight of that here.