To make a long story short; I was stuck with her.
So I decided to teach her how to fetch.
This is how I did it:
Step 1: Find a toy that cats like
Step 2: Make the bag into a ball
Step 3: Keep this in mind (a lesson in cats)
You'll be able to tell if this is something natural for your damn cat or if it doesn't want to play fetch.
Dont get angry with your kitty if she doesn't want to play fetch. Just try different methods to get her to actually see YOU carry the ball back to the starting point (mostly in your mouth). Whenever she actually picks up the ball and tries to bring it back, Reward her! Simple playful pets work great! Once in a while give her a food treat (POUNCE, tuna, etc). Don't spoil her with rewards though. If you spoil her, then she'll just turn into a snobby cat like your friend's cat.
Rewards should be random after she realises the routine.
Step 4: Teach kitty to carry it in her mouth
For my kitten, Dorothy, I took her into a small room (the bathroom). I then sat on one side of the room and after I teased her with the bag/ ball a little, I tossed it to the other side of the room then I, myself, crawled over to the bag/ ball (at this point she will be so interested that you'll probably have to take it from the cat) and put the ball in my mouth and brought it back to where I started.
Let kitty see what you are doing (actually put the ball in your mouth and crawl back to where you started). Do it again. Do it again. Do it again. Keep doing it. I recommend a small room because it makes it easier to go back and forth.
Kitty will eventually learn that with bringing the ball/bag back a reward is in store.
Step 5: Remember, Cats are easily distracted
When your kitty gets sick of it (maybe a leaf blows by and she goes for that), just forget about it and come back to the task at hand later.
Repetition is the key but there is a fine line.
Don't make it into a military drill or your cat will never fetch and someday eat you in your sleep.
Remember, your kitty is not a doggy. Cats will hold grudges.