My Aussie has TONS of energy! And there are some days where it is just impossible to go outside and play (stormy weather, freezing blizzards) so what toys would you recommend to keep him occupied? I will list the toys he DOES have. Red Kong (medium), Black X Kong (large), two indestructible frisbees, 3 balls with tails, rope toys, bones, tennis balls, squeaky balls, and one stuffed animal that he loves. I just want his mind to be stimulated so that when it is impossible to play, he still has something to do.