Combine the honey, lime juice, and 1-1/2 tablespoons of the mint. Pour this over the grapes, mix well, and refrigerate for several hours or overnight.
Divide the grapes among 4 stemmed dessert or sherbet glasses. Top each serving with 2 tablespoons of yogurt. Sprinkle the remaining chopped mint on top as a garnish (or garnish with a thin round of fresh lime).