Fun activities for overweight kitty

My girl, Cleo, is 12 years old and is overweight. She is primarily an indoor cat, and when she goes outside, she sticks really close to the back door. I need some ideas on how to get her to exercise more, as she generally doesn't overeat. I feel her IAMS Indoor/Hairball Formula, which is supposed to be for weight control, and I only give her about 3/4 of a cup per day. She does not eat "people" food except once in a while I give her a little non-fat plain yogurt. I will post a picture of her soon, as I don't have an electronic picture of her here at work. Thanks

Has the vet said anything about her weight? My cat also does not officially overeat--she always ate way less than the packages recommended--but stll beefed up. "Lite" food didn't help, either. After going on a high-protein diet and losing a lot of weight, she gained again with a small serving of "lite" food. She's now on prescription diet food.

As far as activities, the one toy she absolutely CANNOT. RESIST. chasing is her Play N' Squeak. It's a wand toy with a furry, catnip scented mouse that chirps incessantly when it is in motion. She'll chase that thing till she's panting.

Since I put Bijou on wet food with just a little bit of dry for snacking during the day, he has lost a bit of weight and trimmed down. He also eats less wet food than dry food - probably because it's more nutritious.

My cats were not over weight, but I have noticed that they are more active now that I have put up some bird feeders. I have two out and I seem to attract quite a few different kinds of birds. I have one in the front of the house and one in the back. They will run from window to window and then just sit and stare. I know they are more active because I think the bird watching gets them wild. If you are going to be letting your cat outside however I would not recommend this! I hope that helps!

The Cat Dancer is the only foolproof toy I know of for most cats. Mine is pretty sedentary by nature and most of the time that is the only thing that will get him moving at all.

Get a rod, tie a cord a few feet in length to one end of it, tape it down(still swingable/maneuverable by you), and tie a rattling fuzzy mouse to the other end by its tail. Pretty much every cat I've fostered (and my resident cat) loves those. Drag it slooooowly across the floor to get playtime started. You can also "steep" the mouse in a bag of catnip.

Thanks for all the suggestions. I will look for the type of toys you all have described. The fishing pole thing I have does not make any noise, so I will find one that does. (,)>^.,.^<(,)