Those Are Strings, Pinocchio - S3-E22
Corrected entry: In the episode in which Rory graduates from Chilton, she was talking to Dean, early in the episode. He said he has a nephew who was going to be the ring bearer in his wedding. But, Dean only has one sister and at the time, she was only about 10 years old. Maybe 12, but not old enough to have a three year old son. And, never, in any other episode, does Dean have or mention another sibling. How could he possibly have a nephew?
Correction: Actually, early in the show's run, Dean uses the word "sisters" when giving Rory the details about his family. We only ever see one sister, but that would presumably be because the other is older and no longer lives with her parents.
Phixius ★