Do you have an ice cream maker of some kind? Definitely need one to make ice cream! Even so it will come out soft-serve unless you have an electric one. (We only have a hand-cranked kind.)
Almost every sugar-free recipe I'm finding when I do a web search uses artificial sweeteners which I'd avoid more than sugar for a once-and-done recipe. I'm finding a number which use Equal (aspartame), which is a neurotoxin, and/or packs of sugar-free instant pudding, which will be sweetened with either Equal or Splenda, which is sugar bonded with a chlorine molecule.
Here's one which uses grape juice cooked down into syrup, which will have natural fructose from the juice as the sugar:
http://www.cooks.com/rec/view/0,1713,135184-250197,00.htmlHonestly, if you're just serving it this one time for a special occasion, I would seek out organic ice cream or something natural like Breyer's which uses so few ingredients. I have also seen "ice cream" made with coconut milk which is kinda yummy!
You could also serve yogurt sweetened with any number of sweeteners, including agave, maple syrup, xylitol, or sugar (maybe honey), or alternately use a little bit of stevia to sweeten the yogurt (we have a liquid extract and a couple drops is enough to sweeten a whole bowl of yogurt!).