No problem.
String theory is the theory that the most fundamental things in the universe are vibrating strands of energy called "strings". Some strings are "open" and others are "closed" (you can think of this as either a single piece of rope vs a rope tied in a circle). Similar to the strings on a guitar, each string is able to function differently to produce a different result (on a guitar, sound). Depending on how they vibrate (both amplitude and frequency), these strings of energy give rise to everything in the universe. Remember, matter and energy are indistinguishable in physics; hence E=mc2.
When string theory was being developed, theoretical physicists and brilliant mathematicians were competing to map out the language of string theory (the mathematical equations). They were basically all attacking the same problem from all different directions. This caused there to be many different competing "string theories". The math for all of them seemed to be correct. This caused wide spread confusion and scientists turned away from string theory as a viable theory.
In walks a theoretical physicist (from Michigan I believe, his name escapes me) with a couple undergraduate colleagues and flips everything upside down. They realized that all the different competing string theories were correct. They were just describing different sides of the same coin, if you will. The different string theories had different calculations, equations, and number of different dimensions. These guys realized that all the string theories fit perfectly within a 11-dimension universe. The math was beautifully perfect. This 11-dimension, master version of string theory is M-theory. The "M" stands for either "magic", "mystery", or "matrix".
The 11-dimension universe consists of the three spatial dimensions we are accustom to (x plane, y plane, z plane), time, plus seven more that we are unaware of as humans.
So, M-theory and string theory are essentially one-in-the-same. Here are some implications:
1) The Big Bang Theory as we know it could be in trouble. Under M-theory, our universe could have very easily been cause by two D-Branes (basically whole universes) colliding. If true, another D-Brane could be a trillionth of an inch away from your nose and if it was to ever collide with your nose, another Big Bang would happen.
2) Our grade school version of gravity is entirely false. Gravity is nothing more than a force from another universe interacting with our own universe.
3) Parallel universes exists. The probably are connected. They are probably infinite in number. Everything you do in this universe, has a equal and opposite reaction in another. Basically, every choice you have made in this life, in another universe you have done the opposite. Wrap your head around that. Other universes almost certainly have different laws of physics, biology, chemistry, and mathematics. Oh btw, there are probably passageways from our universe to them, also known as wormholes.
4) Eternal return is possible. Nietzsche will be validated in his belief that life is absurd. He went crazy from the implications of eternal return because he thought eternal return was fact.
5) Ghosts, if you believe in them, could be energy trapped in other dimensions.
6) Some people we deem as "crazy" in our society and lock up in a insane asylums might not be crazy at all. They might for whatever reason be able to tap into one of the other 7 dimensions. They would actually be aware of a higher reality than us.
7) It strengths the hologram principal first discovered in the lab. Basically, our reality is nothing more than a hologram. The only thing that matters is information which cannot be destroyed.
8) Given 1,4,and 7, if the universe is finite, and gravity has the power to overcome dark energy and dark matter, the big crunch will ensue. If such a thing happens, Frank Tipler's Omega Point Theory would gain validity. His theory would seemingly predict immortality for everything. Big, big if's, but it's intriguing none the less.
Hope this helps.