Editor's note: The online version of this story was posted on January 7.

When Nintendo’s Wii game console debuted in November 2006, its motion-sensing handheld “Wiimotes” got players off the couch and onto their feet. Now Microsoft hopes to outdo its competitor by eliminating the controller altogether: this past January it revealed details of Project Natal, which will give Xbox 360 users the ability to manipulate on-screen characters via natural body movement. The machine-learning technology will enable players to kick a digital soccer ball or swat a handball simply by mimicking the motion in their living room.