how i met ur mother, big bang, friends... all comedies :)
Seinfeld if you like comedy :)
I think that if your listening isn't that much advanced, you can start by Dr. Phil's shows. They're really great, because you can not only improve your listening skill, but also learn a lot about how to live better. Then you can watch Oprah and then you can watch more informal ones such as funny series like How I Met Your Mother, etc.