How do they get the yellow first down line to show up during football games?

­The virtual first-down line that you see in many televised football games is something of a computer-generated miracle that home viewers have come to love. Find out how this line gets "painted" on the field without painting the players.

Advancements in technology allow the home viewer to see all kinds of information that the fan in the stadium can't see. Learn how do the broadcast stations… » Full Story on HowStuffWorks