Now Playing: 12-12-11 Marketplace

U.K. Prime Minister David Cameron continues to defend his decision not to sign the EU's treaty last week. U.N. delegates in South Africa decided to extend their climate talks this weekend to reach an agreement. Post-revolutionary Egypt tries to figure out to handle its food supply. Zynga might become the second-largest IPO behind Google. And we hear recommendations for the best books of 2011.