There's only so much time in the day, so when possible I like to combine my entertainment with learning a little about the world. With a whole lot in the news about British Counter-Terror efforts, I highly recommend MI-5 a BBC show about, well, British Counter-Terrorism. I'm in the middle of season 2 on netflixs.
The show is riveting. Moral murk, real characters, and a ticking clock make for great drama. Not to mention, educational.
The first thing you learn is that MI-5 is not "The British equivalent of the FBI" FBI agents are basically just Federal Cops. Jumped up reputaions, but really just cops. 5 (calling it "5" makes you sound like you know something) is a domestic spy agency.
Its agents are undercover and spy on Britons the way the CIA spys on foreign Nationials. We really don't have an equivalent. The is a lot of talk of the US getting a domestic spy agency, and MI-5 will show you what it looks like.
UPDATE: Richard Posner Makes the case that we should have our own MI-5.