Hide-N-Seek. Also our Secret Santa last year sent us this really cool treat ball. You put treats in the middle and he plays with it to get them out. Mambo will play with this for hours. He tosses it, rolls it and everything he can do to get the treats out. Even better now that we have the laminate floors. It rolls all over the place.
What kind of a treat ball are you using? Sadly, Rukus has figured out how to get the treats out of his kong with minimal effort....he picks it up in his mouth, drops it on the floor, gets the treats that fell out, and then repeats the process until the kong is empty. *sigh*...he's too smart for us. :-\
"Find it" is also a good one. Pick a favorite toy, hide it somewhere, and tell your pup to find it. You have to start with pretty easy hiding places, but then get more advanced. I usually put my two in a sit-stay on a particular rug as part of the game while I'm hiding the toy, and they can't go look until I release them with the "OK" command. So the game not only keeps them amused, it helps reinforce one of their commands.