I'll go ahead with good confidence and say Paper clips. I mean, come on, just look at them!



More examples to be found here, here, here, here, here and here.

You can do other stuff with them than to hold paper together! For example, bend them to Sakai tops, use them as a haircut on whoever happens to have a magnetic head, making christmas tree decorations, bending them to stupid shapes or this (I don't know what these are doing and why, but they sure seem to be having fun!)

The best thing of all, though, has to be that you'll never run out of them! It's like magic!