Currently watching America: the Story of Us, on Netflix. Other than the fact that everything has been a bit condensed (it really should be 24 episodes, rather than the 12 it is), it's really good and informative. In fact, I've really been on a documentary kick this summer. Other than this, I've watched Cosmos: A Spacetime Odyssey (the new one), Superheroes: A Neverending Battle (a 3 part history on superheroes, and how they've affected our culture), The Bomb (a special on the arms race), and Atari: Game Over (about the fall of Atari, and what E.T. had to do with it) over the summer.
Also, I binged all 4 seasons of Spartacus last month in a little over a week, and I watch Toonami every Saturday (my current favorite shows on the block being DBZ Kai, Akame ga Kill, and Sword Art Online II).