You and your TV have probably build up static electricity. Static" electricity (more correctly called "net electric charge" ) appears whenever the normal quantities of positive and negative electricity in a substance are not perfectly equal.

Remember that everything is made of atoms, and atoms in turn are made of positive and negative electric charges. In other words, your body is just a collection of positive and negative electrical particles. Normally the positives cancel out the negatives, and everything behaves electrically "neutral." No mysterious sparking. But if you ever end up with more negative than positive, or with more positive than negative, then you have a charge-imbalance on your body. You will get zapped the next time you touch a large metal object.

Exactly how can this imbalance occur? Whenever we walk, the soles of our shoes steal some negative charge from the floor. We leave behind electrified positive footprints, and our bodies acquire an overall imbalance of negatives. (Or sometimes vice versa with the negative and positive, since polarity is determined by the type of shoe soles and the type of rug.) After many footsteps, our bodies attain a high level of electric charge and a high voltage. Body-voltage can easily rise to several thousand volts, and the next time you touch someone else... ZAP! The imbalanced charge gets shared between you and your TV for example. The spark is painful because it's extremely hot. It drills into your skin like a white-hot needle, creating a microscopic burned area.