"The Big Bang" isn't just a romping great season finale that resets the entire universe, it also contains several of Steven Moffat's favorite Doctor Who storytelling ideas, most notably a scene in which the Doctor mucks about with the order of events using time travel ("Let's Kill Hitler"), a scene in which a character has to wait for an unfeasibly long time ("The Girl Who Waited," "Hell Bent"), and a scene in which key characters are destroyed, their devastating absence is seen on the faces of the people they love most, and then they are somehow put back together again ("The Doctor, The Widow and the Wardrobe").

Here are a few things to keep an eye out for, the next time you watch:

(The episode is available on iTunes and Amazon.)

This is one of only three Doctor Who episodes that were broadcast on the date shown within the reality of the show. The date within the story is June 26, 2010, which was also the date of broadcast. This had happened in Part One of "The End of Time" (December 25, 2009) and "The Impossible Astronaut" (April 22, 2011).

This story contains the Eleventh Doctor's first direct encounter with a fez, although his Seventh Incarnation had tried one on during "Silver Nemesis" and he had certainly met people wearing them before - not least in "The Pyramids of Mars" and "The Evil of the Daleks". The distinctive Moroccan hat has many associations within entertainment history, including Casablanca (as worn by Sydney Greenstreet) and Raiders of the Lost Ark (John Rhys-Davies), and it's that latter association that probably prompted its inclusion in this episode, given the Indiana Jones feel of "The Pandorica Opens." But for British viewers of a certain age, the fez's most immediate reference point is the comedian Tommy Cooper. He wore his while performing deliberately bad magic tricks and telling daft one-liners, earning him huge affection from the viewing public:

https://www.youtube.com/watch?v=oTY6TxXsK-o

When Steven Moffat mentioned to fellow executive producers Piers Wenger and Beth Willis that he'd written the fez in—largely to make it clear that the Doctor who visits Rory back in Roman times is from a future that we, the audience, has not seen yet—there was a concern that Matt Smith would want to wear it all the time. While the fez in this story was destroyed by River Song, the idea of the hat quickly took on iconic status among fans, and that's why it came back.

That said, the Doctor has a long affection for headwear. The First Doctor was often seen with a black hat, as were his Fourth, Fifth and Seventh incarnations, while the Second Doctor—the greatest single influence on Matt Smith's interpretation of the role—was often seen trying various items of headgear on. He could sometimes be found gazing at other people's heads wistfully and saying "I should like a hat like that," in the manner of the Eleventh Doctor passing a friendly fez.

When Amy tells her younger self, "OK kid, this is where it gets complicated," that scene had to be reshot. Karen Gillan had said the line as "really complicated" at first, and Steven Moffat felt that this added a layer of meaning to the story that it didn't need. As the film crew couldn't return to Brangwyn Hall in Swansea, where the museum scenes were shot, Karen Gillan had to say her line from the Pandorica set instead.

The Doctor says that the fossilized creatures (including a Dalek) outside the Pandorica are "the footprints of the never-were," which is not only a poetic way to describe them, but a throwback to a reference his predecessor made when discussing the Time War, in "The End of Time." When looking back on the worst moments of the conflict, he shakingly remembers "the Skaro Degradations, the Horde of Travesties, the Nightmare Child, the Could-have-been King with his army of Meanwhiles and Never-weres" before concluding that "the war turned into hell."

There are two pop songs played during Amy and Rory's wedding. The Doctor's mad hands-in-the-air dance is performed to Queen's "Crazy Little Thing Called Love" (a wedding staple), while Amy and Rory's first dance is "You Give Me Something" by James Morrison:

https://www.youtube.com/watch?v=UZp6dhheriM

Speaking of the Doctor's dance, Steven Moffat merely noted in the script that the Doctor would be a terrible dancer, and given Matt Smith's physiognomy, the phrase "drunk giraffe" worked its way in. Matt's interpretation of this direction is, of course, his own invention.

Karen Gillan later confirmed that the footage they use of Amy laughing at the Doctor's dancing is just her watching Matt Smith lark about, there was no acting involved.

And we’ll just leave this Steven Moffat quote right here: "My favourite dirty joke in Doctor Who is the title of episode 13 in series 5, 'The Big Bang', [because it's] the night when River began. I laughed a lot when I thought of that."

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