You were expecting River Song, maybe? The latest Dr. Who episode, "The Doctor's Wife," was written by, as you've probably heard, unless you've been hiding under a rock, the popular and prolific author Neil Gaiman. I don't want Mr. Gaiman to give up his day job, but it is clear that he is a Whovian and any additional episodes he'd like to turn his hand at would be very welcome.
"The Doctor's Wife" was an absolutely mad episode (in a good way). Gaiman was able to capture the delivery of the madcap Doctor (Matt Smith) perfectly, and also created a female character that could meet him quirk for dialogue-y quirk. In a reveal that comes very early in the episode, so I don't really consider it a spoiler, a young woman (Suranne Jones) is imbued with the soul of the TARDIS — she becomes the TARDIS personified, or as the Doctor refers to her, Sexy.
TARDIS: Are all people like this?
Doctor: Like what?
TARDIS: So much bigger on the inside?
The episode is full of in-jokes and clever wordplay. The Doctor, Amy (Karen Gillan) and Rory (Arthur Darvill) are drawn to a planet, or a bubble, or ... well it doesn't really matter — that may or may not be home to some surviving Time Lords. As the Doctor investigates and teams up with Sexy, Amy and Rory are trapped inside the now empty shell TARDIS, which is being controlled by an evil entity called House.
It is fun to have living proof that a ship is a "she." Similar to the great sci-fi series Farscape, whose space travelers were on a living (and sometimes pregnant) ship called Moya, the TARDIS is revealed as a living vessel. Gaiman has fun with some Dr. Who lore as the two characters bicker: The TARDIS say she “borrowed” the Doctor and he insists that he "borrowed" her.