We made this last time we went camping. It's fun with a little reward at the end!
1 tablespoon sugar
1/2 cup milk or half & half
1/4 teaspoon vanilla
6 tablespoons rock salt
1 pint-size plastic food storage bag (e.g., Ziploc)
1 gallon-size plastic food storage bag
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. Wrap the bag in newspaper then duct tape. Shake and toss until the mixture is ice cream, which takes about 5 minutes. Open duct tape/newspaper, wipe off the top of the small bag, then open it carefully. Enjoy! (Sidenote: 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.)