Even though video replay may be useful, it's still pretty low-key. So, like George Lucas changing Yoda from a puppet to a CGI, tennis made the leap to computer rendering. The Hawk-Eye system, based on ESPN's Shot Spot feature, uses cameras set up around the court to track the ball's path and create a 3D rendering of where the ball hits. Besides being used to judge if a ball landed in or out, Hawk-Eye can also be used to analyze a player's strategies. In its sporadic uses, Hawk-Eye has proven effective, usually serving to anger the players whose points get taken back from the replay.
Microchip Balls (Soccer)
Fans of the Tottenham Hotspur were up in arms after a game they lost because a ref wasn't paying attention. The team scored an obvious goal, but the linesman didn't see it and simply signaled for play to continue. That prompted soccer officials to unveil a new ball, partially designed by Adidas, with a microchip in it. The chip would signal the official whenever it crossed the goal, thus negating the effect of refs napping on the job. The ball made its debut at the 2005 Under-17 Championship and has made sporadic appearances since. In terms of accuracy, the ball has been a success, although that could also be due to refs actually doing their job. However, some players have complained that the microchip makes the ball travel differently and is harder to control.
Umpire Information System (Baseball)
Being the home plate umpire in baseball has always struck me as one of the most difficult jobs "“ in a split second, you're expected to determine if a pitch was in or out of an imaginary box. To help standardize strike calling and reduce umping mistakes, Major League Baseball instituted a digital check on its umps in the form of Questec's Umpire Information System. The UIS doesn't correct calls on the field; instead, it compares the computer's results to the ump's. The technology stirred up controversy, with players arguing that it didn't take batters' size into account and was making umps scared to make controversial calls. Arizona pitcher Curt Schilling even smashed one of the cameras in his home stadium with a bat after a particularly rough outing. Reportedly, one of the umps told Schilling to break the other one.
Video Replay (Just about every sport)