It is amazing to me that I have a never ending source of kitchen gadgets. Sadly, I use/need them all!
What is a micro plane? It is not a mini-airplane, but it is a mini grater! This is one of those gadgets that doesn't take up a lot of room, and you use will use it more then you think.
Microplanes are most often used for zesting. Zesting is when you finely grate the peels of fruits such as oranges, lemons, and limes (pretty much an citrus). Also commonly used for nutmeg and garlic!
Other things I use it for: grating hard cheeses for sauces, pastas, or any other item in need of some cheese. I finely grate chocolate for decorating cakes, cupcakes, ice cream, and again, anything that needs a chocolate touch. I have also used to on different vegetables in order to throw in some extra veggie power.
Microplanes are very inexpensive, can be found as low as $10.
Now go buy one, you know you want to.