There's a Japanese art form called chindogu, sometimes translated "unuseless invention", which involves creating things that are almost but not quite useful. A chindogu (which must be an actual working physical machine, not just a description) should be a novel way of doing something that's largely pointless, or not worth the trouble, or can be done better some other way.
One chindogu is a cat-food bowl with a built-in blower to cool the cat's food if it's too warm. Another is a pair of platform shoes with compartments that hold a small amount of water, detergent, and laundry; walking powers an agitation mechanism in the heels, so you can wash a small amount of clothes as you teeter down the street. Some might consider the Minsky-Shannon Useless Machine—a device which, when activated, turns itself off—an American chindogu.
I think algorithms can be chindogu too. There are perverse algorithms, such as Bogosort (generate random permutations of the input until you find the one that's in order), which are somewhat chindogu-like, though they don't quite achieve the almost-useful nature or surprise of a good chindogu. Here I'm really interested in algorithms that are interesting but hard to use for anything practical.
(Note for Japanese speakers: Yes, that should probably be romanized as "chindōgu" or "chindougu", but "chindogu" is what's most commonly used.)