The feeling you experience when you rub a latex balloon vigorously against your head then touch a piece of metal is called "static discharge." Though the buildup of unreleased electrons in your body is called static electricity, it is discrepancy between positive and negative electrons that makes a potential for voltage. Static electricity is merely a large amount of that potential that doesn't have an outlet. Finding a proper earth ground and touching it neutralizes that potential, as the buildup of electrons escapes. The term "high voltage" is merely a reference to any kind of energy imbalance. Between a leg and a soft pair of paints, it results in static cling. Between a positive and a neutral copper wire, it becomes an electrical outlet.
An old saying states that volts hurt, but amps kill. Amperage is the rate at which electrons are capable of flowing and, though it has no correlation, high voltages can flow in a dangerously high-amperage rate. Static electricity gathered in a human body cannot build up dangerous amperage because the human body is not a effective conductor. Conductivity is the extent to which a material, such as copper, can conduct electricity.
The charge resulting from static electricity often is temporary in nature, while high voltage in general can be tied to a much more constant source of energy. In the common example of dragging one's socked feet on the ground, the buildup of energy is contingent upon that movement. If the person stops moving, the voltage stops building. In a electrical wire, however, the potential is continuously provided and thus "discharge" will occur continuously.
For a static discharge to be felt, the object must be discharging at least 500 volts. Often, the discharge amounts to thousand of volts. This amount is a lot of potential, but not nearly the levels achievable by high-voltage power lines. High-voltage power can carry anywhere from 69,000 to 500,000 volts. By contrast, the voltage in a traditional American power outlet is only 110 volts.