Grab a cupcake tin and line it with paper baking cups. Scoop an appropriate amount of ice cream into each. Each cup is one serving.
When they're all filled, pop the tin back into the freezer for several hours. When it's time for ice cream, just hand out the pre-portioned cups and you're done!
Added benefits: Nobody having to wait (and whine) for ice cream AND the ability to have individual servings of any flavor at your supermarket!