The Play & freeze ice cream ball is pretty neat, but a little pricey @ $28+
“With the unique Play & Freeze Ice Cream Maker, you can make ice cream anywhere! You dont need electricity, just add ice and rock salt in one end and ice cream mix in the other endthen have a ball as you shake it, pass it or roll it! The ice cream mix can be as simple as cream, sugar and vanilla. Try flavors from our recipe list included or make up your own. Made of durable polycarbonate, its lightweight, portable and easy to clean.” [via] – Link.
Here’s a DIY version that could be put inside some type of sphere too… MAKE 06 – Home Made Ice-Cream… without a refrigerator! Lower the temperature of ice with salt and use it to freeze your own ice-cream! – PDF & Link.