Remove strings from rhubarb, wash, and cut into 1/2″ pieces. Wrap rhubarb in cheesecloth and tie shut. Bring sugar and water to boil. Put cheesecloth in the syrup and simmer over medium heat for 30 minutes or until it thickens. Remove cheesecloth, squeeze it to get the juice out. Pour syrup into a clean, dry bottle and cork tightly. To mix add 1 part syrup to 3 parts water and add 2 ice cubes per person. Serve well chilled.