"Shark!" Someone yelled that at me. From a moving car. I was walking down the street, carrying three sacks of groceries. Did something about me remind him of a shark? Was it a reference to a television program, or perhaps West Side Story? Maybe just something he's yelling a lot these days? Odds are I'll never know.

Heckling is commonly defined as the interruption of a public performance with loud unfriendly statements or questions. Classic heckling scenarios include political speeches, stand-up comedy, and certain spectator sports (particularly baseball, basketball, and ice hockey). A good heckle requires creativity, timing, and voice projection. The successful heckler feels that he has had a role in the event; that he has borrowed the spotlight, however briefly, from his mark; that he has been heard. Heckling is uniquely satisfying.

And as evidenced by my encounter with the young man while carrying groceries, the best heckles make little to no sense. Riding a city bus last week, I heard a fellow passenger exclaim, "Hey, you forgot your legs!" out the window as we pulled away from a stop. A few blocks later he yelled "New money!" in the general direction of an Urban Outfitters. Later the same day, a friend spontaneously yelled "Well, are you skating or dying?" from my passenger window as we passed some nondescript teens loitering outside 7-11.

But as live artistic endeavors struggle to compete with electronic media and ticket price inflation puts increasing distance between athletes and ordinary fans, traditional heckling opportunities become harder and harder to come by. Whither the heckle, in the new millennium? The answer -- the “drive-by” has all the elements of a classical heckle: the public setting, the yelling, the relatively captive target. The interrupted performance may be a commonplace physical activity, carrying groceries. Or it may be the critical theorist's notion of performance of social identity, such as that of a suburban teenager.

Prepare your bellowing voice, your biting commentaries, your nonsense phrases. All the world's a stage, and all the men and women marks. "Shark!"