Hide and Seek

Kitty lost his favorite toy, and you bought/found him a new one.
Instead of just giving it to him, try putting it in a sack/bag and put all of it in the floor. Let Kitty dig through the bag and find the toy on his own.
You can do this with his current toys also. If you use a plastic bag, cut several holes in it first so that kitty will not suffocate, and then be sure to put it away when kitty is done playing.