This may be only my imagination, because as far as I can see I'm the only person who's mentioned it, but in this week's episode of Doctor Who, Night Terrors, I could swear there is a sequence just before the credits which features a subliminal glimpse of most of the old Doctor Who title sequences. It's when young George sends the message "Please save me from the monsters" and it flies through space all the way to the Tardis.
You can see the episode on iPlayer here. The sequence I'm talking about lasts just a few seconds at 1.55.
Now, look at all these Doctor Who title sequences then tell me you don't see glimpses of them.
Okay, I might be totally imagining it, and it's a bit jerky on iplayer, but look at these:
Isn't that the purple globe from the McCoy credits? And in this next picture can I not see McCoy rocks flying towards me?
Is this Peter Davison's face dissolved into stars superimposed over the McGann stars?
And isn't this Tom Baker's face in stars flying towards us?
And... I'm going mad aren't I? It is only me who's seeing these things. I'll get that coat Janis Joplin lent me.
UPDATE: I've stuck more screen grabs, of the classic credits, here on Gallifrey Base. And sent Mark Gatiss a tweet asking if I'm just imagining it.