Douglas Adams should hopefully need no introduction and if he does I'm going to be incredibly lazy and point you to his entry on Wikipedia. This little gallery was inspired by the fact that, when I was unpacking books following the move, I discovered that I had two sets of Hitch-Hiker's Guide to the Galaxy, one amongst the SF books and one amongst the TV and Radio tie-ins (as it was initially based on a radio series).
The strongest memory I have of the series dates back to Seacon '79, the World SF Convention that was held at the Metropole in Brighton. Hitchhiker's had been broadcast in 1978 and re-broadcast a couple of times that year, which is when I first heard it, ahead of the seventh episode that was broadcast on Christmas Eve 1978.
At Seacon, the convention committee had put aside a small room to play tapes of Hitchhiker's. A lot of visiting—mostly American—fans had never heard of it. The first 'broadcast' attracted a few people--to be honest, I can't remember how many, but there were definitely spare seats. Word-of-mouth soon got around about the show and a second 'broadcast' demanded. It then played continuously(?) to packed audiences, the little room bulging at the seems. Or that's how I (partly) remember it happening anyway.
What I do distinctly recall is the Hugo Awards ceremony. The award for Best Dramatic Presentation, which included Hitchhiker's in the nominations, was won by Superman: The Movie. The announcement was greeted with little enthusiasm (there may have even been a low hiss), even from fans who had voted for the film. Christopher Reeve walked onto the stage to pick up his rocket and apologised for winning!
The Hitch-Hiker's Guide to the Galaxy [Film tie-in]. Pan 0-330-43798-4, 2005. Cover © Touchstone Pictures.