In "Dear Albert" - a staged reading of letters written by Albert Einstein - you get the impression of a man grappling with big ideas...and a complicated lovelife. Alan Alda, actor and co-founder of the Center for Communicating Science at Stony Brook University, discusses why Einstein's letters so moved him. He's joined by Brian Greene, co-founder of the World Science Festival and professor of mathematics & physics at Columbia University. They are both taking part in lots of activities this week, including the announcement of the winners in the "What Is Color?" challenge.