The Infinite Improbability Drive is a wonderful new method of crossing vast interstellar distances in a mere nothingth of a second, without all that tedious mucking about in hyperspace. It was discovered by a lucky chance, and then developed into a governable form of propulsion by the Imperial Galactic Government’s research team on planet Damogran.The principle of generating small amounts of finite improbability by simply hooking the logic circuits of a Bambleweeny 57 Sub-Meson Brain to an atomic vector plotter suspended in a strong Brownian Motion producer (say a nice hot cup of tea) were of course long understood – and such generators were often used to break the ice at parties by making all the molecules in the hostess’s undergarments leap simultaneously one foot to the left, in accordance with the Theory of Indeterminacy.
Many respectable physicists said they weren’t going to stand for this, partly because it was a debasement of science, but mostly because they never got invited to those sorts of parties. Another thing they couldn’t stand was the perpetual failure they encountered in trying to construct a machine which could generate the infinite improbability field needed to flip a spaceship across the mind-paralyzing distances between the farthest stars, and in the end they grumpily announced that such a machine was virtually impossible.
Then, one day, a student who had been left to sweep up the lab after a particularly unsuccessful party found himself reasoning this way: If, he thought to himself, such a machine is a virtual impossibility, it must logically be a finite improbability. So all I have to do in order to make one is to work out exactly how improbable it is, feed that figure into the finite improbability generator, give it a fresh cup of really hot tea… and turn it on!
He did this, and was rather startled to discover that he had managed to create the long-sought-after golden Infinite Improbability generator out of thin air, which passes through every point in the universe simultaneously so there is no telling what species you will be before Normality is restored. It startled him even more when just after he was awarded the Galactic Academy’s Prize for Extreme Cleverness he got lynched by a rampaging mob of respectable physicists who had finally realized that the one thing they really couldn’t stand was a smart-aleck.
The drive's first installation in a spacecraft, the Starship Titanic, to ensure that it was Infinitely Improbable that anything would ever go wrong with any part of the ship, went horribly awry because the engineers did not realize that with the quasi-reciprocal and circular nature of all Improbability calculations, anything that was Infinitely Improbable was actually very likely to happen almost immediately. The ship underwent total existence failure almost immediately. After being perfected, the drive was successfully installed in the starship Heart of Gold, where it mostly worked fine aside from the occasional tendency to, against all probability, pick up unexpected passengers by itself.