If I remember correctly, the first episode of Dr. Who where Douglas Adams was the listed writer or script editor (one from the Tom Baker years), there's a scene where the Doctor was sitting down reading a book from Oolon Colluphid (he of the trilogy of philosophical blockbusters) and says "he got it wrong on the first line".

Oh, and 7 year old spoiler alert if you haven't seen the movie...
Boomchuck1, there were three times in the movie where Douglas Adams' face (or part of it) were seen. One was one of the planets on the factory floor of Magrathea, second was at the very end of the movie when the Heart of Gold was firing up the improbability drive (just before the credits and right after Marvin says that Milliways is at the other end of the universe), and the third - well, it was part of his face. Adams' nose was modeled and used in the temple on Viltvodle VI. It can be seen at the end of the stairwell bannister.