Can a single guest judge — bland as wilted leaf of iceberg lettuce, unqualified as a 2-year-old gleefully clutching the wheel of an 18-wheeler — ruin an entire two-hour telecast of an Emmy-nominated reality competition series? Maybe not entirely.

But if this week’s installment of So You Think You Can Dance was an Olympic swimmer, then Canadian songbird Carly Rae Jepsen was like a lead weight around each leg, …READ MORE