A few things I have read, seen, and discussed lately have pointed me in this direction. Metaphysics is defined on Wikipedia as the study of "the fundamental nature of being and of the world." It's really a fairly vague term, and sometimes it is difficult to understand what metaphysics really encompasses.
I understand metaphyics more generally to be the study of the relation between the mind and reality, which is really just a decomposition of the word into "meta" (beyond) and "physics" (the laws of reality). I have to admit that metaphysics is a subject that I am really fairly poorly informed about in any formal way. I have never taken a class or read a textbook on metaphysics. The good thing, though, is that I think this is true of most people. Most people would probably say that the topic of metaphysics is too erudite and disconnected from everyday thought to be of any interest to them. I wanted to share, then, how some metaphysical ideas and concepts have made their way into popular thought.
One of the post recent and popular examples is the movie Inception. In my opinion, this film is really a study on the blurring of the lines between dream (an analogy for perception) and reality. A central theme of the movie is that in dreams our subconscious perception and expectation actively shapes the world around us.
One idea that I thought was very interesting was that the main characters actually developed methods to help them determine whether or not they were in a dream. If it was a dream that they were in control of, their subconscious automatically filled in all the little details their mind searched for to see if they were dreaming. So even down to the smell of a room or the color of fibers on a rug, their dream would be accurate. This meant it was very difficult for the main characters to decide whether or not they were in a dream, and they had to develop ways to disconnect their physical perception of an object from their expectation of it, and when they found a difference that was when they knew they were awake.
The idea that a difference between perception and expectation signals reality is pretty interesting. It ensures that our world is not wholly a product of our mind, but is influenced by things outside of ourselves.
Another metaphysics example I thought of when watching this movie was the book (also a movie) A Scanner Darkly by Phillip K Dick. In this book, the main character is investigating a group of people as a government spy, and as a part of the process begins taking a drug that has serious effects on his cognitive abilities. The mix between his reality of living two lives (his government job and his "cover" identity) and the fact that the drug is causing the two hemispheres of his brain to become disjointed and compete lead to some interesting observations about what reality is, or whether there are even multiple realities. In case you think that this syfy stuff may be too heavy for your taste, PKD's short stories also inspired Total Recall, Blade Runner, and Minority Report, so you may already have a taste for his work.
On a completely different plane, the recent craze of "the power of positive thinking" is another example of metaphysics. The basic idea of this is that you can, in effect, project your positive feelings onto the world around you. By feeling positive yourself, your perception of reality changes enough that your actually picture of the world changes. You are changing your reality. As a Christian, I can tell you this works: if you start off a day in a prayer of thankfulness, your reality does seem to change. This begs the question: if our reality is so sensitive to our thoughts, is it really that simple to define what reality itself truly is?
To wrap up, I wanted to mention that I think many philosphers are overly dismissive of the topic of metaphysics. I think if many of them would approach the subject with a but more leeway for deep though and self questioning they may bump into some interesting ideas.
One rather frustrating example for me was Atlas Shrugged, Ayn Rand's fictional exposition of her philosophy of objectivism. Objectivism is a very pratical philosophy that focuses on immediate physical reality as the only true nature of the world. Her metaphysics are summed up in two words: objective reality. This combination of dismissal of all but the immediate and her clearly atheistic inclinations causes her arguments to really fall flat when it comes to some of the big questions.
One example is the source of this objective reality. To the Chistian, God is the ultimate reality. To the atheist, matter is the ultimate reality. Both have the same question to answer: what is the source of this ultimate reality? To the Christian, the answer is God is eternal and sourceless. But what is the answer of the atheist? Is it simply that matter is eternal, having always existed? Perhaps a better answer is that time itself is an illusion, a simple consequence of the physical laws dictating matters creation and evolution. But what about these laws, these constructs for matter? Does this view of matter as a timeless mix of law and energy, intimately subject to our perceptions of it, really fit within the narrow framework of objective reality. I'd say it's a tight fit at best.