This is a couple of years old, but cool:
What if, seconds before your laptop began stalling, you could feel the hard drive spin up under the load? Or you could tell if an electrical cord was live before you touched it? For the few people who have rare earth magnets implanted in their fingers, these are among the reported effects — a finger that feels electromagnetic fields along with the normal sense of touch.
The magnet works by moving very slightly, or with a noticeable oscillation, in response to EM fields. This stimulates the somatosensory receptors in the fingertip, the same nerves that are responsible for perceiving pressure, temperature and pain. Huffman and other recipients found they could locate electric stovetops and motors, and pick out live electrical cables. Appliance cords in the United States give off a 60-Hz field, a sensation with which Huffman has become intimately familiar. “It is a light, rapid buzz,” he says.
The author had a magnetic implant put in his own finger:
I would circle my finger with a strong magnet and feel the one in my finger spin. In time, bits of my laptop became familiar as tingles and buzzes. Every so often I would pass near something and get an unexpected vibration. Live phone pairs on the sides of houses sometimes startled me.
New sensory modes using low cost, low tech methods—why not? Show me a few hundred people who like their magnetic implants and I’d probably do it too.