I will give up my Segway for one of these
 

OK, someone come and get my Segways, I am getting one of these.

http://www.flixxy.com/volkswagen-levitating-car.htm

Now THAT is cool.

But, where is the trunk for my PT?

Pretty cool video. Too bad it's just film magic.

I can give you a boring number of reasons why it's not presently feasible even as a real prototype. But I'm pretty sure that when and if it does become feasible, it won't be levitating that high. There's just no point in making it more difficult. And it will take a lot more than "minerals underground" on the part of the roadway to make it work.

Bob you just rained on my parade. I want one or better yet to use the technology on my computer chair.

Sorry. Reality is like that sometimes.

If you don't mind needing a supply of liquid nitrogen, lining the floor with a whole bunch of very strong magnets, and some rather expensive materials, you could do a computer chair today.

You can get some of the stuff you need here:
http://www.quantumlevitation.com/

Somewhere I've seen video of one people put together big enough to stand on and travel a few meeters.

There are other techniques, too -- more complex, but perhaps more practical (cheaper, easier to maintain, no cryogenics).

But a simpler option would be to get a big blower, feed air to a chamber under your desk, and drill lots of little holes -- like an air hockey table.

But, my chair is not a desk, my chair is also a space craft. Moon in 2 minutes. I have posted pictures beforer. But I dream, an engineer always brings us back to, as you say, "Reality.

You'll need a much bigger blower then. Hang onto your hat!

When I heard that bit about the minerals in the ground, but then saw the machine on an elevated highway, I was quite amused.

If it would have enough minerals (natural magnetism?) to lift that vehicle when it is on an elevated roadway or bridge, I cannot imagine anyone being able to keep fillings in their mouth, or glasses on their noses...

Still, if it could exist, it did look kind of fun. There was one scene where it was viewed from a distance, coming from a side street from the left, and then turning onto another street, where there was a soda can or some other debris under it, and it seemed to get blown out from under. I thought it was well done, even if not technically correct.

I don't see how a mag lev kind of system could not work, but it would take quite a bit of infrastructure, and clearly a change to current propulsion systems. I can see how a permanent bed could be implanted in the roadway, and frequency variations used with self propelled vehicles. My understanding of current mag lev technologies is that they propel the vehicles not unlike the movement of charges in a stepper motor. I am thinking of a steady series of charges, with dial in frequencies available, more like the signals in a fiber optic cable. We shall see, the future is arriving faster all the time, and far smarter people than me are working on these things...

Those doors are great for taking out the bad guys. Open them at the right moment and BANG the bad guys are gone! :)