Gunnar likes to play a hide the toy game. I'll put him in a down/stay in one room, or on one side of my house, and then go hide a toy or object somewhere else in the house or in the yard. Then I go back to him, and release him with a "search" command. He'll tear off and find the object.
I have him locating my wallet and keys now- a very good thing since I misplace them often.
You can start real easy- lay the object out in the open. Gradually make it harder to find- shoved between couch cushions, up higher (to keep them from always thinking it'll be at ground level). I've even hidden stuff in the kitchen cabinets and he'll have to mark that he's found it by barking or pawing at the door.