Having dogs makes me very aware of animal enrichment. Dogs are intelligent, social, and capable of highly destructive acts, so enriching them (even if we don't put it that way) is very important. The "Kong" is a great enrichment tool for amusing the dog when you can't be there to amuse the dog.

Of course the great thing about dogs (the reason I own them) is that the best form of enrichment for them--the social bond you share, the playtime, and the training, are rewarding for the owner as well.