Run out and buy Ben and Jerry's Ice Cream and Dessert cookbook. In the meantime, here are two quick-and-dirty ideas:

Buy one large can of frozen juice (I usually use the "exotic" varieties such as pineapple-guava-raspberry or banana-oragne-passion-fruit; there are lots of these available in the Us.) Thaw the juice concentrate. Add one can of water. Beat one egg white until it is foamy and mix it into the fruit juice mixture. Freeze in your favourite ice cream maker. This makes just less than one quart of very smooth ice.