Off topic, strictly speaking, but when in LA – Donald Liebenson's story in the LA Times alerted me to a cultural anniversary that really is worth celebrating: 30 years ago today, on November 17 1978, CBS broadcast the world's most mind-boggling movie spin-off: the Star Wars Holiday Special.

It's possibly the finest travesty of a movie icon ever committed to televisual history – made even finer since the whole project was taken completely seriously. French and Saunders or even South Park parodies have nothing on this: Carrie Fisher, Mark Hamill and Harrison Ford, as well as Peter Mayhew as Chewbacca, are all centre stage in the Holiday Special, in which the plot – the loosest possible use of the term – is that Han has to get Chewie back to his planet, Kashyyyk, to celebrate Life Day (don't ask) with his family, whom we meet in the second scene. If you get that far, that is, and your eyes aren't bleeding after the title sequence.

The first part is set in the house of the wookiees, a sort of 70s condo in the trees, which is the scene for drag-queen cooking demos, a lot of grunting (wookiees can't speak), and the climactic arrival of Han Solo. On the way, there's a Star Wars cartoon, a performance by Jefferson Starship and their holographic guitars (John Williams doesn't make an appearance in the show, to his eternal credit), and the final horror of Fisher singing a hymn to Life Day to the accompaniment of glorious late-70s cheap special effects.

You can watch all of it in instalments on YouTube, or if you can't take the Wagnerian sweep of the complete thing – and I couldn't - try a five-minute digest of its two tortuous hours. Liebenson calls it "television's guiltiest of pleasures", but it's the jaw-dropping awfulness of the idea and its execution that's astounding, and hilarious. Who in their right mind thought this was a good thing to do? George Lucas, for one: even if he didn't direct the show, he wrote the back story – which is probably why, today, he refuses to talk about it.