Some dogs have a wealth of toys, but they still get bored. When your dog is bored with a toy, put it away and bring out another toy that you had taken out of circulation a while ago. It will be like a new toy, your dog will get just as excited. Keep the majority of your dog's toys in a bin in the closet. Rotate each toy to give your dog variety and a change of play. When you take them out of play, give them a wash and remove any that are broken. This activity will save you money as well as provide stimulating variety for your dog. But if they have a really special toy that they love, leave that out for them. Play fair - your dog will love you for it.
Your dog will love a change of pace from their everyday life. Next time you take the car to the car wash, take your dog along. They will be stimulated with so many new sights and sounds, and they will enjoy new situations. Take them when you go for a drive to the cleaners, or to collect the children from school. They will get to meet a lot of new friends and receive multiple pats for this outing. Even if you have to go and drop off the mail or pick up a parcel, take your dog. Your canine companion will soon know that the jingle of the car keys means a trip and they will be bouncing at the door to get out to the car. Stop on the way home for a run in the secure dog park and let them run with the hounds and have fun. By the time they get home, they will need a nap.
If you can think of nothing else to do, here is a quick fix. Pop the leash on your dog, then go outside and start jogging. But not just jogging, mix it up a bit. Jog for a block, then sprint like mad for a block, then walk a block, and then repeat. Keep varying the pace, it will keep your dog focused on you. When you get to the park, you can jog and weave in and out of the trees. You can even hop, bounce, or whatever you like. Give your dog a treat for the sprint stages or maybe for weaving in and out of the trees. Your Bostalian will love never knowing what you are going to do next. There are benefits for both dog and human here, you both will have a lot of fun and get super fit at the same time.