Interesting article by Brian S. Hall. A bit on the touchy-feely side (pun intended), but the possibilities are exciting:
Haptic technology —haptics— uses force upon the skin to deliver real-time tactile feedback. These physical sensations are created by tiny motors called actuators. Done right, haptics can mimic the feeling of a pin prick by a wearable that tracks your blood sugar, simulate the plucking of virtual guitar strings on a tablet screen, or re-create the physical recoil of a phaser from your favorite game controller.
I don’t get why anybody would want to replicate the prick of a blood glucose monitor, but the rest are all great.