[REBROADCAST FROM September 25] Ed Ruscha is a pioneer in the world of Pop Art, an artist with a sense of humor, a knack for words, and a great eye for color. Now, in the biggest US exhibition of his work, the Museum of Modern Art features the new retrospective, Ed Ruscha / Now Then. The exhibit features more than 200 works, including a new installation of Ruscha's iconic, "Chocolate Room." Christophe Cherix, chief curator of drawings and prints at MoMA, joins us to discuss the exhibit, running through January 13.