Here's Video Of The Fastest Tennis Serve In History A 6'10" Croat named Ivo Karlovic broke Andy Roddick's fastest-serve record in the fourth set of a Davis Cup doubles match yesterday. In 2004, Roddick's yellow ball traveled 155 mph (or 249.5 km/h); Karlovic's went 155.96 mph (or 251 km/h)....
