Apply mild electric current to your head, improve your motor skills

Balakar describes experiments of Reis et al. , who

...trained two groups of 12 volunteers each to use a joystick to move a cursor as quickly and accurately as possible through an obstacle course on a computer screen. The task was difficult enough to ensure that performance would improve over five days of practice.

During the practice sessions, all participants had electrodes connected over the primary motor cortex, the part of the brain that plans and executes movements. One group was stimulated with a mild current through the connection and the other was not. After five days of practice, the group that received the current was significantly better at the task, both in speed and accuracy.