I've recently discovered this show that probably many of you know: "Family Guy" and I've found that it's a wonderful way to improve your English for many reasons.
First things first: It's super entertaining, you'll never get bored of it, which means you are more likely to spend more time improving your listening skills than if I asked you to listen to academic lectures for example.
The second reason is: Improving your pronunciation; especially if you're trying to develop an American accent, this will help you more than anything else because you'll listen to a native speakers having conversations all the time.
Also, never forget to practice the shadowing technique.
You'll come across many words that you've never heard before, and if you can go the extra mile and look those words up, this will help you expand you vocabulary.
Do you still need more reasons? I don't think so, just try it out for yourself and tell me what you think about this show.