1 medium cantaloupe or honeydew, or
1/4 watermelon (for about 4 1/2 cups diced)
1/2 cup orange juice (see note)
1/2 cup granulated sugar (see note)
Seed and dice the melon. Stir together the citrus juice and sugar until mixture is fully liquid (sugar needn't be completely dissolved). In batches, if necessary, puree melon with the sugar mixture and any liquid from dicing. (A blender is best for this; if using a food processor, keep at it a while, scraping and stirring occasionally, to produce a puree, not just chopped melon). Taste and add sugar if necessary.
Freeze in ice cream freezer following manufacturer's directions for sorbet. If you don't have an ice cream freezer, pour mixture into shallow bowl and freeze 3 hours or until firm, then scoop into a mixer bowl and beat with an electric mixer about 10 seconds. Refreeze.