From this week's New Yorker
 "The Cellular Age" (George Plimpton)

 A man was standing at the corner of 56th & Lexington a few weeks ago waiting
 for the "Walk" sign to appear. Next to him was a woman who said very
 distinctly, "Margaret, I will have nothing to do with that man or his dog."
 Since only the two of them were waiting at the curb, he assumed that she was
 talking into a celular phone. "How common it is these days," he said later,
 "to hear people chatting away in buses, or striding along the sidewalk
 talking quite loudly, apparently to themselves -- behavior that, if it
 weren't for the little handheld sets, would be an easy ticket to the loony
 bin." He went on to say that he had looked over idly and was surprised to see
 that the woman was not holding a cellular phone but was, in fact, talking into
 a cupped hand held close to her ear, her little finger aloft in simulation of
 an antenna. "That's right," he said. "She was carrying on an imaginary
 conversation into an imaginary phone."

 That was not the end of it. When she caught him staring at her, she reached
 up with her free hand, folded the little finger -- the "antenna" -- down into
 her fist, and guided the whole into the pocket of her suit jacket. "What was
 surprising," the man said, "was that I had to hold back from apologizing for
 eavesdropping."