Can anyone give me a short explanation of the HBO series Girls?

I was flipping the channels at my hotel the other night and ran across the series Girls. I don’t have HBO at home – I had heard that the lead actress is controversial (not sure why) and I heard that the show was interesting (again, not sure why).

I watched it for about 35 minutes, and with each passing scene, it seemed more an more incoherent.

But maybe I am missing something. Can anyone give me the Cliffs Notes version of Girls and why it is popular?