Why did the Doctor call River "Mrs Robinson?"
In The Impossible Astronaut when Rory, Amy and River exit the Tardis into the Oval Office the Doctor introduces them as:
My top operatives The Legs, The Nose and Mrs. Robinson.
Amy and Rory are presumably The Legs and The Nose (either because she's often wearing short skirts or because of Rory's silly shorts). But why is River "Mrs Robinson"?
Best Answer
Was about to write the following myself, but as I made a search for it just to verify everything, I stumbled upon this slightly more detailed answer on the Wikipedia page for Mrs. Robinson:
The 2011 Doctor Who episode "The Impossible Astronaut" has the young-looking Eleventh Doctor introduce his middle-aged future wife River Song in 1969 to President Nixon as "Mrs. Robinson", a nod towards a hinted-at romantic relationship between the two in the Doctor's future and in River's past (due to time-travel). River's line "Hello, Benjamin" spoken in the Doctor Who episode "Let's Kill Hitler" is a quote from a line spoken by Anne Bancroft as Mrs. Robinson in The Graduate.
Pictures about "Why did the Doctor call River "Mrs Robinson?""
The Doctor In The White House | The Impossible Astronaut | Doctor Who | BBC
More answers regarding why did the Doctor call River "Mrs Robinson?"
Answer 2
Second the above answer, but I believe it's also an in-joke/hint from the writers that spoilers River is Amy and Rory's daughter. In The Graduate, Benjamin is briefly and uncomfortably seduced by the mother, but ends up falling for the daughter. In Flesh and Stone, Amy has a similar, but toned down seduction scene with the Doctor, but he, like Benjamin, ends up falling for her daughter.
Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.
Images: Thirdman, Thirdman, Thirdman, Tima Miroshnichenko