Explore just how powerful your dog's sense of smell is by hiding a treat in a place in your house that's difficult to get to. Leave a trail of scent by rubbing the treat on a few spots along the way. You can also buy toys that let you put a treat inside and prompt your dog to figure out how to get it out. This problem-solving task is good for stimulating your dog's mind.
Dogs have a natural drive for chasing prey, so bring this out by tying a toy or stuffed animal to a stick. Drag it slowly and stop occasionally, rather than waving it around quickly. The slow pursuit helps your dog learn to focus.
Champion dogs can leap through hoops, and your dog can too. Just find a hula hoop and encourage him to jump through by throwing a treat through the opening. Once he gets the hang of it, reward him with praise and affection.
Fetch is a great way to tire out a dog full of energy, while giving him exercise and fulfilling his natural instinct to run, run, run. Retrievers are naturals at fetch, but any dog can learn.
When you're playing with your dog in the backyard, try setting up an obstacle course for him. Put out boxes for him to jump over or set out a few cones. Encourage him to weave between them as he runs by having him follow you and going through the motions - slowly at first, and then more quickly.