A couple of years ago, I demoed a gadget called the Celluon Magic Cube laser keyboard – it projects an image of a keyboard on your
desk and you can use it to type into any Bluetooth enabled device.
It was definitely an attention grabber, but it wasn't particularly easy to use – you have to hover your hands over the keyboard (so it’s not good for touch typing) and there are some weird effects trying to use the shift keys. I used it for a couple of weeks, but it just didn't work very well for my purposes - maybe it would have worked better as a portable keyboard for use on a plane?
It should be in full production in July and is available for pre-order from the Kickstarter site for about $60:
Here’s a video of it in use.
The only problem I have with it (having only seen pictures of it) is that it looks like the head of a tiny Transformer. I would have preferred a plain, black monolith…