It was a gray day in late 2005. I was sitting at my desk, writing code for the next year’s iPod. Without knocking, the director of iPod Software—my boss’s boss—abruptly entered and closed the door ...

Imagine using your iPod and a regular old microphone to record studio-quality audio. Or sitting on a commuter train and playing Othello, Pong, Tetris, or Asteroids. All this and more is possible when ...