For about 1 pint, you'll need:
+ blood oranges, 4 pounds
+ 1 lime or 1 lemon
+ water, 1 1/4 cups
+ sugar, 3/4 cup (Small? Okay, not really.)
Chill the metal canister of your ice cream maker.
Zest 3 of the oranges. Simmer the zest, the sugar and the water over medium-high heat until the sugar has dissolved and the water has reduced by half. Chill.
Juice all of the oranges, and the lime or lemon, making sure to pass the juice through a sieve. Combine juice with syrup; chill for at least one hour. Churn in your ice cream maker until thick and cold. Place in a plastic container, and freeze for at least 3 hours before eating. Garnish with thin strips of lime or lemon zest; enjoy!