Dr Who - The Green Death
I remember distinctly seeing this episode as a repeat on BBC2 as an adolescent. I wonder what it was about this particular episode that stuck in my mind; was it the political conflict between environmentalists, coal miners, and a multi-national petro-chemical corporation, the combination of Dudley Simpson's eerie pitched percussion and Dick Mills's electronic screams, or was it the Cronenbergian body horror of the strange maggot creatures lurking down the mine that so piqued the interest of my pubescent mind?
This story, from what we might call the 'golden age' of Dr Who (roughly speaking, season six to season fifteen) is also notable for the use of the sonic screwdriver as a kind of sonic weapon to temporarily paralyse the maggots; a believable love story between Jo Grant and Professor Jones (not to mention more than a twinge of jealousy from the Doctor - albeit the resigned jealousy of an old rake who knows there will always be more fish in the sea); a computer that enjoys humming Beethoven and Wagner to itself and paraphrasing Oscar Wilde; and the Doctor's attempt to fox said computer with one of Douglas Hofstadter's 'Strange Loops':
"The following sentence is true. The preceding sentence is false."
In Godel, Escher, Bach : An Eternal Golden Braid, Hofstadter uses these self-referential loops, common to both the drawings of M.C. Escher and the canons and fugues of J.S. Bach, to explain the emergence of self-consciousness in an apparently rigidly deterministic system such as the human brain, or that of a computer.
The other nice thing about this 'golden age' period is the gradual introduction of a whole host of semi-regular characters, beyond the Doctor's immediate assistant(s), who pop up from time to time: not just Brigadier Lethbridge-Stewart, Sergeant Benton, and Captain Mike Yates, but also The Master and the sinister High Council of the time lords.