Light Blue Optics launched their Light Touch projected display technology back at CES 2010, but the majority of the video demos we saw were performed in relatively low-light environments. Obviously the team are braver now, since they've taken their prototype - which uses a laser projector to create an image, and sensors to track finger-movement around that image - over to show to Robert Scoble.
Video demo after the cut
The prototype creates a roughly A3-sized display on any surface, and since laser pico-projectors don't require manual focusing the image is always clear and crisp. An infrared light source is then used to track your fingers as they interact with on-screen icons and controls.
Light Blue Optics are apparently working on other versions which will use bigger projectors; they'd be able to create wall-sized interactive screens which would still be reasonably portable (especially if you're comparing them to a 42-inch LCD touchscreen or larger). As for performance in reasonable lighting, rather than the murky CES demos, the Light Touch unit looks pretty clear, certainly good enough for the rather stark UI the company have developed for the prototype.