Check this out, This recipe and idea is from the website Kaboose. The crazy kids at the Consumerist swear that it works. Anybody game for a stab at this?
Plastic Bag Ice CreamWhat you'll need:1 tablespoon sugar1/2 cup milk or half & half1/4 teaspoon vanilla6 tablespoons rock salt1 pint-size plastic food storage bag (e.g., Ziploc)1 gallon-size plastic food storage bagIce cubesHow to make it:Fill the large bag half full of ice, and add the rock salt. Seal the bag.Put milk, vanilla, and sugar into the small bag, and seal it.Place the small bag inside the large one, and seal it again carefully.Shake until the mixture is ice cream, which takes about 5 minutes.Wipe off the top of the small bag, then open it carefully. Enjoy!Tips:A 1/2 cup milk will make about 1 scoop of ice cream, so double the recipe if you want more. But don't increase the proportions more that that -- a large amount might be too big for kids to pick-up because the ice itself is heavy.
Other users report that it's an easy way to make sorbets as well, just use fruit juice in lieu of the half and half.