Favourite Doctor Who joke

So basically, what is everyones favourite Doctor Who related joke in a comedy? I've been noticing quite a few in the shows I've been watching lately and wondered what everyone thought.

My personal favourite I only saw this morning in the first episode of Chelmsford 123, where the Romans are walking along the road and you see the TARDIS materialise in the background. It was just the last thing I expected and it cracked me up no end...

My second would have to be in one of the new ideal episodes where Moz thinks he is having a heart attack and a sceptical Nikki asks him "What are you going to do, regenerate?"

Anyone have any other favourites?

Knock knock.
Who's there?
Doctor.
etc

Sontaren: We have an intruder!
Dr: How'd he get in? In through the window?
(In-tru-da window. Geddit??!!!)

The Extras Christmas Special featured Andy Millman as a slug type monster in Doctor Who and David Tennant killing him with salt.

Whats Doctor Who's worst type of food?

Dalek Bread

Who are the Narns worst enemy? The Baltis!

A Babylon 5 joke slipping through.

http://www.vidilife.com/video_play_1078493_Family_Guy_w_Doctor_Who_Sequnece_from_Blue_Harvest.htm

In one of the Sylvester McCoy episodes (I think it was Silver Nemisis) he puts on a pair of glasses to confuse someone. When Ace asks what he was doing he replies 'making a spectacle of myself'. Or something along those lines.

Fourth Doctor (Tom Baker): 'Robots of Death'

Uvanov: "I suppose it’s also a coincidence that as soon as you two arrive, three of our people are killed. Well?"
The Doctor: [looking at the floor for a bit]"Oh! I’m sorry, I thought it was a rhetorical question. Yes, it’s just a coincidence."

It's all in the delivery, but gives me a laugh every time... infact all of the dialogue from that scene is quite wonderfull.

Uvanov: "Who are you?"
The Doctor: "I’m the Doctor, I assume you’re in command here."
Uvanov: "Yes, what are you doing here?"
The Doctor: "Just standing here talking to you."
Uvanov: "I should be very careful if I were you."
The Doctor: "No doubt you would."

There's an episode of a show, with some of the league of gentlemen,

where they do how the theme tune was created very funny.