Training can be lots of fun for you and your dog. In addition to heeling, coming front and finishing, sit, stand and down stays and the other basic obedience trial stuff, retrieving, show posing, rally and agility stuff, I have taught my dogs tons of tricks. They close doors and drawers, get me tissues, pick up their bowls after eating and bring them to me at the sink, find and deliver things on walks, get toys by name, etc. But for me the real fun are the silly things. I had one that would whisper in my ear on the cue "tell me a secret", some "raise your hand", some play patty-cake, some dance, several cock their heads on cue ("what do you think?"), a couple shake their heads 'no' on the cue "you wouldn't do that, would you?", and lot of other fun things. One of my favorites (don't try this at home

) we called "got rabies?" and my girl would bare her teeth and snap in your face. You had to know her - it was totally in control and funny - no thought of aggression involved. I always joked that I was training her in case she got a starring role in Old Yeller. -- Guess I should have mentioned these were/are all Labs. My Old Yeller is over Rainbow Bridge now, no doubt using her brilliant mind to be the Queen in heaven.
The more things you teach your dog the smarter they become and the deeper your relationship grows. Dogs love to be challenged and, if you make it fun, most of them love to learn. It doesn't matter how old they are - it's never too late. I love to train little puppies, but I rescue dogs and foster dogs of all ages and they all get training if they come to my house!