The buildup of charges on an object is called static electricity. Unlike current electricity, which flows through an object, electrons that make up static electricity are stuck in a negatively-charged insulator. If connected with an appropriate conductor, the electrons will flow into it to neutralize the object.
The most common cause of static electricity is two objects being rubbed against each other and then pulled away. If one of these is an insulator, it is possible for it to pull away electrons from the other material. This leaves the insulator negatively charged, but the electrons can't escape. If a person touches the material, he or she will receive a static shock, which is due to the electrons escaping into and through the body.