Hoverboard in Back to The Future Part II
Watching Michael J Fox ride a hoverboard in Back to The Future Part II inspired a whole generation. It's 'supposed' to come to market in 2015 and we sincerely hope it does, because the Segway just doesn't do it for us.
Where the hell is it?
The Mattel-branded hoverboard replaced wheels either with fans, which couldn't be powerful enough to hold up a person, or some kind of battery-powered magnet to repel the Earth, which would need too much energy. In spite of an incredibly persistent urban myth (fuelled by director Robert Zemeckis), gravity cannot be defied so easily.
I want one now!
Impressively, single-person hoverboards exist in the form of the Arbortech Airboard and Future Horizon hoverboards that work like personal hovercraft. Okay, it's not exactly the same as Michael J Fox's board, but it will let you float about on the street.