Yes , I know I thought the same thing, Yeah right!!
Well I am here to tell you it works and was the coolest thing ever. Jake my 4 y/o thought this was the best thing.
Thanks to the super mom over at Charlie Brown's Teacher for this awesome science experiment lesson. You can read more on her site about the science behind it all.
So if you were looking at the "Slushy Magic" that is advertised on TV, don't waste your money. Also, there is really no mess to clean up doing it this way.
All you needed to do is fill a quart size baggie with salt and water, place in the freezer over night (which doesn't freeze it turns to slush), then you place the small baggie inside a large zip lock baggie pour the kool-aid mix in the large baggie and shake for a couple minutes and you have a slushy mix.