There are many different dogs related sports. Dog Agility, Treibball, Flyball, UpDog,Dock Jumping, Canine Disc, etc.
WHY:
Each offers a different but fun way to engage with your dog, have fun and keep your dog fit!

WHAT:
Dog Agility is very popular, with several venues offering slightly different versions of this sport in the US (AKC, CPE< NADAC, UKI, USDAA, TDA, etc) and around the world. You can do it for fun or be a serious competitor. Treibball is popular in Europe and is gaining popularity here is some states. Dogs have to move large balls into a net like a soccer gaol mouth. Flyball is team sport for dogs, where they race over a line of hurdles to a box which releases a tennis ball from the spring loaded pad when pressed by the dog, and then race back to their owner with the tennis ball. UpDog was provides fun games for owner and dog which includes disc tosses, agility, freestyle and other games. Dock jumping/dock diving is another sport gaining in popularity where dogs compete in jumping off a dock for distance or height into a body of water. Skills of course are jumping and swimming- both which can be taught with a fair amount of ease. Canine Disc where humans throw and dogs catch discs at a distance and in freestyle and is popular around the world. HOW: It is easy to get started by joining a class suitable for a novice dog and even a young dog can learn the basics and the skills without putting any pressure on them to jump before their growth plates are closed. Check out training clubs and venues in your local area. Go visit a competition, talk to competitors and you will be surprised at their passion for their sport and their love of their fur companions. All of these sports are enjoyed by all ages of humans and all types of dogs.