It is titled, aptly enough, The Night of the Doctor.
I was very fortunate to click through to the mini-sode first thing in the morning, and avoided all spoilers.
It was a big shocker, because somehow, someway in this age of the Internet, the secret was not leaked. But now we can discuss it.
|"I'm a Doctor. But probably not the one you were expecting."|
The last time he was seen in the role was 1996. That was for the t.v. movie - his one and only (until now) visual appearance as the Doctor.
No surprise, I can't stop pondering The Night of the Doctor. Sure, McGann's surprise appearance was an undeniable wow! factor, but there's more than that.
It's no throwaway extended scene - it's a story, loaded with backstory presented with tight writing.
This rundown sums it up well.
I would add a few other points. First off, this is not a role McGann dusted off after 17 years. Yes, he has not been on-screen as the Doctor in all that time, but he has been playing the Doctor in audio-plays for a number of years now. He knows exactly how his Doctor acts and sounds, and he was able to bring it all to those 6+ minutes of the mini-sode.
Also, the themes present throughout the current run of the series are in here, too. One aspect of the new show has been exploring how the Doctor saves his companions and how they, in turn, save him - from himself. It is very telling that here at the end, when the Doctor chooses to no longer be "the Doctor," there is no companion to talk him out of his decision.
For those non-Whovians reading, think of it as an incredible piece of Doctor Who flash fiction. It might even be interesting to watch it and see how much backstory you can work out. I have an advantage there, but I still think a helluva lot was conveyed on-screen.
The Night of the Doctor
Between Moffat's laser-focused dialog and McGann's pitch-perfect performance, this might be the best 6+ minutes of Doctor Who ever.