Many dogs can often be placed into one of two categories; those who prefer the familiarity and comfort of the home and those who enjoy the beauty and splendor of the great outdoors. Leonbergers definitely fit into that latter category and they'd certainly love an activity like backpacking - in which you and your dog take a trip through the wilderness with nothing but the supplies you can fit into your backpack.
Most of the other activities on this list focus on honing your Leonberger's physical attributes, but this is one of the few that emphasize training your dog's brain. Leonbergers can learn how to sit, stay, fetch, and roll over just the same as any other breed of dog can. Grab a hold of a few dog treats and begin training your dog how to complete tricks on demand.