Your dog has an incredible sense of smell, so teaching it to find rewards using its nose is a great way for stimulating its mind. Place four or five opaque boxes or containers on the floor face up and together. Place a treat under the bins while your dog searches, then take it to the boxes and encourage it to sniff them out. When you see that it approaches the award, pick up the boxes and congratulate it with enthusiasm and let it eat the award. Keep adding more but separate boxes to increase the challenge as sniffing skills increase.