h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

As previously discussed the Swiss Army knife has many blades, things to pull out, gizzmos and the like. However their greatest claim is that they are at the heart of most Improbability drives. They do not have to be at the physical heart of the engine but can be just lying around doing nothing in the general vicinity of the engine.
The theory goes like this, the probability of selecting the correct knife or extracting a toothpick instead of a pair of tweezers at the first attempt is so improbable that the researchers for the development of the improbability drive installed a Swiss army knife in the initial startup sequence for the drive. At 30 seconds before the planned take off the pilot would think, 'Damm it, Ive got a piece of Dingoes Kidneys stuck between my teeth, I must remove it.' He would pick up the knife and attempt to remove the toothpick. This possibility is of course highly improbable. From this very small event (or non-event) a chain reation would start, culminating in the main improbability drive kicking into action. If however the correct applicance was removed this was considered to be so highly improbably that it would put the engines into hyper improbability mode. Useful when the mother of the Dingo has just tracked you down as you pick out parts of her child from your teeth.
Swiss army experts soon found that anyone could do this and so the speed advantage that they had gained was soon lost. To overcome this they created larger and larger swiss army knives with more and more things in them. The latest model has now been dropped from production. It had a combine harvester, an accordian and 48 different length cross head screwdrivers (all the same size) along with all the other usual things. The improbability factor for this model was calculated to be 'I to power 942'. When it was installed in a test ship, scientists soon found out that this power rating was wildly off the mark. Just the mere thought entering your head that you could lift such a knife and select anything, especially if the combine harvester was still operating, was so vastly high that the whole unit dematerialised and has never been seen again. This is why on very dark, still nights you can often hear an accordian playing eeriely in the heavens.