The trouble with a series as it gets older is it can feel like a tradition, and tradition is the enemy of suspense, and it's the enemy of comedy. It's the enemy of everything, really. So you have to shake it up.

Brainy's the new sexy.

The Doctor: It's my nose; it has special powers. Nancy: Yeah? That why it's so...? The Doctor: What? Nancy: Nothing. The Doctor: What? Nancy: Nothing. Do your ears have special powers too?

We have a plan to top it. And I do think our plan is devastating. We’ve practically reduced our cast to tears telling them the plan … we’re probably more excited that we’ve ever been about Sherlock.

Madame Kovarian: The anger of a good man is not a problem. Good men have too many rules. The Doctor: Good men don't need rules. Today is not the day to find out why I have so many.

Think you've seen it all? Think again. Outside those doors, we might see anything. We could find new worlds, terrifying monsters, impossible things. And if you come with me... nothing will ever be the same again!

Come on, Rory! It isn't rocket science, it's just quantum physics! -The Doctor (Matt Smith)