"The Infinite Improbability Drive is a wonderful new method of crossing interstellar distances in a few seconds; without all that tedious mucking about in hyperspace. As the Improbability Drive reaches infinite improbability, it passes through every conceivable point in every conceivable universe almost simultaneously. In other words, you're never sure where you'll end up or even what species you'll be when you get there. It's therefore important to dress accordingly. The Infinite Improbability Drive was invented following research into finite improbability which was often used to break the ice at parties by making all the molecules in the hostess' undergarments leap one foot simultaneously to the left in accordance with the theory of indeterminacy. Many respectable physicists said they weren't going to stand for that sort of thing, partly because it was a debasement of science, but mostly because they didn't get invited to those sort of parties."