in other news, david letterman, i love david letterman. just a new york institution at this point. he opened up on cbs this morning speaking to charlie rose and says he has really battled with depression. and who knew? this is someone who makes so many other people happy. he's been pretty skeptical about taking depression medication. so it's been quite a battle that he's dealing with. but it's just terrific that he opened up about it, because it's a battle so many americans have, that people have. >> it will be interesting to see what he does. his contract is up in 2014, but they say a lot of comedians do have a darker side. they have that jovial funny person you see on tv. a lot going on underneath. >> his rumor is a little acidic. and lastly here, gangnam style, the most watched youtube video. the south korean rapper now, to show you how successful that