This has been circulating around for a while, but it was new to me so perhaps it'll be new to others as well.
In one scene during 2001: A Space Odyssey
, the character of Dr. Heywood Floyd uses a "zero gravity toilet" while he's on the space station. He's shown briefly examining the lengthy list of instructions on the wall next to the toilet.
Stanley Kubrick was so obsessive over details that, instead of using gobbledygook, placeholder text for the sign, he actually had someone create a list of toilet instructions. Film buffs have extracted this text, and it's available for purchase as a poster (perhaps to hang in your bathroom) or printed on a t-shirt. (I won't link to any specific retailers, but they're easy enough to find using Google).
Far Out magazine suggests
the zero-gravity toilet instructions may have deeper meaning within the broader context of the film:
Perhaps, thus the ‘zero-gravity’ toilet instruction is the only intentional joke in the film. In a scene aboard the space station, Floyd is seen peering at a detailed and convoluted instruction manual on the use of the zero-gravity toilet. Kubrick’s disdain of instructions for the understanding of the film highlights the irony of a page long instructions from the zero-gravity toilets. In an interview, Kubrick’s explained the zero-gravity toilet was the only intentional joke in the film. That evolution and technological advancement would lead to convoluting of tending to basic human needs is well worth a snigger. Despite its ambiguity, Kubrick doesn’t “want to spell out a verbal roadmap for 2001”. Kubrick’s film doesn’t come with an instruction manual, but the zero-gravity toilet does.