At Corea and Hancock's performance, crowd-pleasers and timeless classics

If ovations were cherry blossoms, Chick Corea and Herbie Hancock would have been up to their knees in petals at the Kennedy Center Concert Hall on Friday night. Yet, as pleased as they were with the resounding response, there were moments during the nearly two-hour, sold-out performance when the jazz-piano legends seemed to find even greater delight in each other's company and in the playful gamesmanship that ensued.