Banana carrying cases
This genius invention has made it to many other countries, but it originated, like all the inventions on our list, in wonderful Japan.
The banana carry case stops you nutritious and tasty piece of fruit from becoming the weird, smelly mush at the bottom of your bag when you get your food out at lunchtime. A perfectly preserved banana, providing you with all the potassium you need and none of the 3 hours spent in the bathroom cleaning out your rucksack.