The TARDIS does something "new" that the Doctor didn't know it could do.
A character first seen in the Series 6 opening story returns.
We meet a new race of *****.
Amy has a flashback.
A gag from The Curse of Fatal Death is evoked through The Doctor's friendship with a famous psychoanalyst.
The Doctor gets it wrong, more than once.
We see Amy and Rory sleep together.
The Doctor does something very similar to Amy that he performed in Day of the Moon.