Director Ang Lee discusses his latest film, "Lust, Caution." And a documentary filmmaker traces the troubled history of three Southern counties where whites systemically banished African-Americans residents around the turn of the 20th century. On today's Please Explain, we'll learn the value of a dollar as our experts tell us all about currency rates. But first, a local filmmaker reveals how one once-impoverished Brooklyn neighborhood is reacting to gentrification. Amy Eddings sits in for Leonard today.