I gotta tell you, having driven just about every car with a multifunction knob, I can't get excited about any of them. But this interface from Visteon might have legs. It's a molded hump of sorts that fits the human hand and places dedicated buttons under your fingertips. The buttons can be used to control just about anything. I spent a couple of minutes using it in a Mazda5 demo car to control video screens, an iPod, and side-view cameras, and it seems to have an intuitive feel. Visteon has been putting it in police cars for a few months and is currently trying to convince carmakers to offer it in typical passenger cars.