We've been having some problems getting our kitty in shape (she was about 18 lbs when we brought her home, and we got some weight off of her, but the less we feed her, the less she moves so getting her to burn some calories hasn't been easy).
Our old apartment was rather cramped and there was only one window accessible to her. In the new apartment there's a lot more space, and she's been playing with her toys for extended periods (not just a bat or two) every day (which WAS not true in the old apartment).
We've found a new game that she LOVES. We bought one of those little pen lights. We had one before, but the light was about 4" in diameter, and she'd watch it move around on the floor, but wouldn't try to "catch" it. The new toy has two ends and two lights one large like the old one, and one tiny (just a speck of red light).
She watches the big light, but LOVES the red speck and will run all over chasing it. I always assumed that she was unaware that we were providing the light, but this morning she was "begging" for something - sitting on her hind legs with paws tucked to her chest like a little bunny rabbit or kangaroo.
What she was looking at was the box that holds the penlight, and hubby told me she was wanting him to play chase the spot with her. Sure enough, when he took the box down for it's perch and set it beside him on the couch, she ran to the box and started pawing at it (there are no treats or anything else in the box that would be of interest to her).
I was amazed. Hubby played with her for a while, and then put the penlight away. She wasn't quite ready to end the game and started pawing at the box again.
Hubby limits her playtime though, because she loves it so much she'll play until she gets out of breath, and gets a bit wheezy. The first time he played with her, she actually seemed stiff and sore the next day (she's got one bad hip), so he's trying to get her to build up her strength and stamina just like a human would.