The Hitchhiker's Guide to the Galaxy: Fit the Fourth

 "We demand rigidly defined areas of doubt and uncertainty!"

This episode is, of course, where the novel ends: it is also, if I recall correctly, where we diverge from the radio series. But that's after the ecxplosion at the end: until then we hae plenty of Douglas Adams' signature absurdity to look at.

The whole thing about Deep Thought and the Ultimate Question is conceptually awesome, of course, however dated the computing looks forty years later. Yet there's more going on than this- the ridiculing of philosophers (personally, I think we need rather more of them in today's accessible cultural media, but...) and the fact that they behae exactly ike the more rigidly-minded trade union leaders of the time. I somehow doubt Arthur Scargill would have enjoyed this episode much.

Yet we also have an absurd, timey-wimey series of events cause by Arthur's tremendous difficulty with his lifestyle,and a wonderful sequence about the mice offering to buy Arthur's brain: there will never again be a sitcom quite like this. And that's before we even get to the glorious piss take of cops at the end...