1In 1-quart saucepan, heat water, sugar and gingerroot to boiling over high heat, stirring until sugar is dissolved. Reduce heat to medium-low; simmer uncovered 5 minutes. Remove from heat; cool. Strain. Refrigerate ginger syrup until well chilled.
2To serve, in large pitcher or punch bowl, mix 1/2 cup of the ginger syrup and the lime juice (keep remaining ginger syrup refrigerated for later use). Add cranberry juice, lime slices and cranberries.