Recent science fiction films have shown some very intriguing technological ideas, some of which are not as incredible as you might think.
Take Steven Spielberg's Minority Report. In the film, police officers fly around using jetpacks. First designed by Bell, the helicopter people, in 1961, it was in fact called the rocket-belt.
There were several different rocket- and jet-powered versions, but they never really caught on due to problems with lack of manoeuvrability, range, and pilot injury on landing.
Personal flight is now heading in a new direction. An American company, Millennium Jet, have designed a strap on helicopter called the Solotrek.
It uses a normal piston engine to drive two fans which the pilot controls using a fly-by-wire system.
If anything breaks or fails a rocket deployed parachute will lower the machine and pilot safely to the ground, even from low altitude.
Solotrek is initially aimed at the military, but civilian versions are planned too.
Deadly sound
Jetpacks are not the only sci-fi staple that really exists. Already sonic weapons are being used to knock down opponents.
Since the 1960s, researchers have known that very deep noise, below the threshold of human hearing, can cause flesh to resonate, even distort vision.
But it has proven difficult to make a powerful sound generator small enough to be portable, and being able to accurately direct the sound over a distance.
Now, using higher frequencies, an MIT student has developed a device called an audio spotlight that can focus a tight beam of sound onto one spot several hundred feet away.
A competing company, American Technology, is marketing a similar device. It is also said to be developing a more powerful rifle-sized version called a Directed Stick Radiator, intended for use in psychological warfare and crowd control.
Computer control
How about newspapers that update themselves? Well, smart reusable paper is already being sold. Gyriconmedia in the US are one company who markets it.
You would need some sort of wireless link to update the paper, but those are also available now.
But it is the scenes in Minority Report showing voice and touch-activated computers that have had a lot of people drooling.
Why, nearly 30 years after the birth of the PC, are we all still stuck with keyboards and mice, and computers we can't properly talk to?
Some of the stuff needed to make a scene like that happen is available now. However, getting computers to accurately interpret human speech and gestures is more difficult.
It will become possible as chip speeds approach the 10GHz mark because the more times a second a computer can guess at what you're saying or doing, the more chances it will get it right.
And 10GHz chips are not that far away. Intel have said the current Pentium 4 could be pushed up to 10GHz.
The seeds of a lot of these technologies are here now. What is now needed is copious money for research and development and a willingness from technology companies to take big risks.