From an article at The Feature on haptic interfaces:

Haptics (from the Greek term "to touch") is already a money-making technology in the gaming, medical, graphics and automotive industries. Typically, computers don't provide tactile feedback and must resort to sounds and visual indicators to represent things you'd normally feel in the real world. But haptics bring physicality back into the digital domain by generating the sensations of pressure, temperature, vibration and texture. Anyone who has picked up a game controller with a well-built rumble mechanism knows how much better the game-playing experience becomes when they can feel explosions, potholes in the road, collisions and so on.

Doctors and nurses in training can learn what it feels like to insert a catheter into a patient's arm by practicing on a dummy equipped with a force-feedback haptic simulator that lets them feel the pop of a needle puncturing a vein. Animators can use a 3-D armature device to mold a virtual clay lump on a computer monitor. And if you get a chance to take a ride in a late-model BMW, check out the iDrive knob, which can switch from smooth rotation to stepped clicks depending on the particular function it's controlling so that information is imparted to drivers' fingers instead of forcing them to take their eyes off the road.

...via BoingBoing