Why, you'd play video games on it, just like NASCAR driver Dale Earnhardt Jr. did at the Charlotte Motor Speedway. As website Joystiq points out, it took 57 workers four months to complete the 332.5 ton, 720p screen, which is comprised of 9 million LEDs.

Dale Jr. Takes World's Largest HDTV For a Test Drive at Charlotte Motor Speedway [Charlotte Motor Speedway via Engadget via Joystiq]