Humor is not the first thing you think of when you hear the name of Ludwig van Beethoven intoned. And yet, as Paul Neubauer, Tara Helen O'Connor and Aaron Boyd, the three performers of his Serenade in D major for Flute, Violin, and Viola, attest, he was not averse to indulging an impish spirit in this unusual piece, performed at the Church of the Archangels in Milies, Greece.