a question this week from the "gps" challenge is how did moammar gadhafi address president obama in a letter this week? was it, "a," to our son his excellency, "b," to your most honorable sir, "c," to my brother in arms, "d" to my fellow african? stay tuned. we'll tell you the correct answer. make sure you go to cnn.com/gps for ten more questions. while you're there, check out our website, the global public square, where you'll find smart takes, including mine on world affairs, the economy and much more. book of the week, i read a novel over spring break and i wanted to share it with you. it's really great. "the imperfectionist" by tom rachman. a series of interlinked short stories about a group of journalists at a newspaper in rome. a smart page turner. if you are an aspiring