To be completely honest, I've always been pretty curious as to what string theory is and how it is supposed to work (and not just because of Sheldon Cooper).
Origionally I was completely off as to what I thought it was all about. My previous notion was that string theory strung together the four fundamental forces of nature (gravity, electromagnetic, strong and weak), showing how they can interact. This actually has very little to do with string theory. String theory is more about the structure of matter as we know it. When considering electrons, most consider them to be microscopic points of matter. String theory, however, suggests that electrons are rather constructed as looped strings, thus giving them the ability to oscillate and move in ways that a point would be incapable of. Theoretically such is completely plausible, and has been effective in many models. However there has been no conclusive scientific data yet to prove that such is truly an accurate way to describe the universe.
I'm sure of course this is an extremely basic understanding, and considering there's countless PhD's out there still struggling to prove it, I've no doubt the complexity of it truly goes above my head. But to think that our understanding of the basics of the universe could be misplaced... tell me that's not fascinating!