How can i get my cat to play or exercise a little more?

So i have a bit of a chubby kitty, shes gained some wait since ive been in school (shes not to the point of it being a risk to her health though) and ive noticed she doesn't play as much as she used to when i lived in a house full of cats. I dont have the money to get her a friend so instead i was wondering if anyone can recommend types of toys or something that may get her to play and be a bit more active.
She plays with her toys when im doing work which i have to do for hours on end and she mainly bats the mouse into the wall and falls asleep. So i want to get her a toy that she can have fun and be active with while im busy doing my work (which is normally painting or writing)

So any ideas? oh and yes i own a laser pointer and a mouse on the stick.

thanks for any ideas you give by the way

My kitties love DaBird toy, which is a feather on a stick that mimics the natural flight of a bird.  You might also consider changing her to an all wet food diet and/or a grain-free diet to help her slim down a bit.  Going to scheduled feedings over free-feeding might also help her slim down.

oh wow i didnt know it was the dry food that makes them heavier thats actually super helpful and thanks ill have to get her the bird toy you described it sounds like shed love it

My dry-food-only cat got chubby and played less and less.  Just like humans, physical activity isn't as fun when its uncomfortable to run and jump!

She developed diabetes too - too many carbs, not enough exercise, overweight.  We switched to a wet diet and she lost weight, her diabetes went away and she was overall a happier, peppier cat!.

Da Bird is a great toy.  We are also having a lot of fun with the Ripple Rug.