Some people believe that a Technological Singularity will arrive in this century. The singularity is described as:
the hypothesized creation, usually via AI or brain-computer interfaces, of smarter-than-human entities who rapidly accelerate technological progress beyond the capability of human beings to participate meaningfully in said progress. Futurists have varying opinions regarding the time, consequences, and plausibility of such an event.
Basically Artificial Intelligences advance beyond human intelligence to the point where those AIs can design ever more intelligent AIs or continually make themselves more intelligent. These intelligences could solve all of humanity's problems such as energy, pollution, overpopulation, hunger, etc.
Humanity would be reduced to a sideline observer (Unless this intelligence explosion is coupled with some sort of human/computer marriage). People might be able to download into machines achieving a sort of immortality, allowing for interstellar exploration, and possibly the colonization of other planets. We could use the Singularity technologies to create cloned or engineered bodies (or just live as cyborgs or robots) to explore, settle and live on these new worlds.
Of course this is all dependent of the AI's allowing humans to survive at all.
None of the arguments above matter at all though, if the Singularity has already occurred and we are living in a computer simulation, as this site suggests as a possibility.
The position of this theory(posited by Dr.Nick Bostrom), is summed up nicely in this New York Times piece by John Tierney which suggests that a sufficiently advanced civilization will start to run computer simulations on computers with more computing power than the brains of all the people on earth. We could just be virtual people living in a simulated virtual universe. Not only that, but the advanced civilization would likely run more than one of these simulations to factor in numerous variables, and increase the likelihood that we already live in one of these simulations.
Tierney follows up with an article on the probability and ethics of running such simulations. HERE Reader comments present argument for and against.
A second followup rebuts arguments suggesting the impossibility of the necessary computing power here.
Of course any simulation could contain internally consistent physics that may or may not reflect the physics of the 'real world'. It could be that the physics within the simulation are simpler than the higher order physics of the 'real world' and we couldn't know. Think about the simpler physics we simulate in video games and 3D animation. The physics in those situations are only as complex as they need to be for the simulated world appear realistic.
We needn't worry that nothing is real, though, because everything and everyone within the simulation is real to everything and everyone else(in the simulation). If I throw my coffee cup against the wall, even if it is only a simulation, it still breaks, I can still cut my hand on a shard of broken glass, feel the pain in my simulated brain, and ultimately it is all real to the virtual me.
Think about it too long and it gives you a headache, but it also presents some interesting possibilities. One could conceivably travel to parallel worlds via a network connection, or we could figure out how to 'hack' reality and do some really weird stuff (if the simulation would allow it). Perhaps these things have also already occurred and explain lots of paranormal things like ghosts, flying saucers, alien abductions etc.