You might try cat fishing. Even my old man - Boomer aka Boogie who is almost 11 will beat the girls out of the way to cat fish.
Buy a child's fishing pole - one of the really short ones. Replace the hook with a safety pin. Attach a furry mouse to the safety pin. Get their attention by dangling the mouse in front of them. When you get their attention - cast the mouse down the hall or across the room. When they start to follow it - start reeling it back. They will play for HOURS if you let them. The more activity the retreival is - i.e. varying speed, dips, jerks, etc. - the better.