Cable ties.

Cable ties are a nice solution to a myriad of problems. I especially like the fact that they come in all sizes and can be used for all kinds of things. I personally think they are a great invention and I love them for the fact that they can corral all the wiring from my computer or stereo system in a neat little package that makes life easier when cleaning and moving things. It also keeps me from kicking the wires out from the plugs.
I really like them for securing things to my bird cages and in need they can even secure the door to the bird cage. While a bird could effectively chew through them, they do work for temporary door holders.
They can be used inside the engine compartment of a car to hold hoses and wires. I've seen them used to hang things from ceiling grids and curtain rods. They can be used in gardening to hold things to a fence or stake. Such a simple little invention with so many uses. I have seen that they even now have cable ties in a large version that are used as handcuffs. I'm not sure how effective they are in this capacity, but I have seen them used and they seemed to work pretty well.

Here is a pretty unusual use for them. They are being used as a necklace, although it doesn't look very comfortable to me. I think I will stick to the more traditional use for now.