Since flyball's beginning in the early 1970s, it has grown to be a wildly popular dog sport all around the world. There are two national sanctioning organizations, and for the best description of the sport, you can visit their pages. World record holding teams with both organizations finish races in just over 14 seconds.
The North American Flyball Association, Inc. (NAFA®) was established in 1984. Visit them on the web at http://flyball.org, and specifically enjoy their About Flyball page at http://www.flyball.org/aboutflyball.html.
The United Flyball League International, Inc. (U-FLI) was established in 2004 with a goal of introducing innovation to the sport. Visit U-FLI online at http://u-fli.com; learn their perspective on the history of the sport at their What Is Flyball page.
Well, there is more explanation below, but really, if anyone wants to know "What's Flyball?", just show 'em this. THIS is flyball: