They're called PufferSpheres, apparently, and they're made by PufferFish Ltd., a firm in Edinburgh. How do I know? I just got a nice e-mail from PufferFish's Mr. Ben Allan, thanking me for my kind (and kind of juvenile, though he was nice enough not to mention that) words about his remarkable product. (While my verdict on Coldplay was mixed-to-favorable, my estimation of the vidi-balls was an eleven-point-oh.)
I'd post a photo of one of the vidi-balls in action, but despite all of the picture-takers that David Malitz mentioned in his review in the Paper of Record, I can find only photos of the balls glowing in different colors -- none that illustrate their unique video-projection properties. You can check out PufferFish's site for some quality demo reel.
Mr. Allan continues:
And nice 'balls' centred punnery too - something for which we have a particular penchant, but not often the balls to go in for publicly!
No, Mr. Allan, thank you. Your balls were unquestionably the best thing about this most entertaining show.