The Sundance Film Festival is an annual film festival founded by John Earle, Sterling Van Wagenen, and Robert Redford. It appeared only in the Season Two episode "Chef's Chocolate Salty Balls".
Background
Robert Redford and his aide Phyllis are seen at a Sundance Film Festival in an unnamed mountain town, where the town is seen with a massive group of people and directors. Redford tells Phyllis that the town used to be small and quiet before being taken over by the large crowd and gaining several fancy buildings. They decide to move the next festival to South Park to turn it into another busy and expensive town like the previous one.