Students at Israel's Bezalel Academy of Art and Design were tasked by General Motors to come up with a way to "help rear seat passengers, particularly children, have a richer experience on the road". Judging by this video, I'm guessing they stared at the rear seat windows, then their smartphones and then back at the windows and thought "Hey, why not whack some Angry Birds on there and call it a day?".
OK, so the "Windows Of Opportunity" (WOO) project, as it's called, has a little more to it than that. The obvious application of touch-sensitive rear windows is to provide distractions for undoubtedly bored passengers. GM, however, is interested in more fulfilling activities, specifically "stimulating awareness, nurturing curiosity and encouraging a stronger connection with the world outside the vehicle".
This direction was apparently inspired by studies that suggested car passengers feel separated from their external surrounds. As a result, GM's keen on augmented reality -- that is, having the projected images interact with the environment they're being projected onto. Passengers can then manipulate the virtual elements to complement the real world.
Car windows get enough finger marks on them without encouraging your kids or passengers to gift them with their bodily oils for enjoyment purposes. Other than that, as long as it can't inadvertently project distractions onto your windshield, I'd be happy to give it a go.
GM says WOO is currently a theoretical endeavour, with nothing slated for production models, but I'm sure if some promising concepts come out of it, there will be engineers slaving away in front of AutoCAD in short order.