S1, E19: While Elliott (Sarah Chalke) and Turk's (Donald Faison) parents pay a visit to see them present at a medical conference, J.D.'s (Zach Braff) father Sam (guest star John Ritter, "Three's Company") makes a surprise visit, leaving all three interns in a state of emotional distress as old parental behaviors come into play. Meanwhile, Carla gets the biggest shock of them all when she discovers she is exactly like Turk's mother (guest star Hattie Winston). John C. McGinley and Ken Jenkins also star. Markie Post also guest stars as Elliott's mother, Lily.