Several organizations sponsor agility trials. Each organization has slightly different rules for standard agility and also has its own set of auxillary agility games.
CPE, one of the newer groups, allows all pure and mixed breed dogs (except wolf hybrids) to run in a wide range of agility game events. It seems particularly committed to dog-person teams having fun.
In addition, meets are sanctioned by other groups like ASCA, the Australian Shepherd Club of America) and JFF, Just for Fun, both of which offer competitions for pure and mixed breed dogs and their partners.
Other Doggery Agility Pages
Animated Image of Agility Tunnel by Graphics From Fuzzy Faces Free Doggy Graphics.