The Ember Island Players - S3-E17
Sokka: Listen to this: The Boy in the Iceberg is a new production from acclaimed playwriter Pu Won Tin. He scowered the globe gathering information on the Avatar. From the icy south pole to the heart of Ba Sing Se. His sources include singing nomads, pirates, prisoners of war and a surprisingly knowlegable merchant of cabbage.
Answer: The pirates are from the episodes "The Waterbending Scroll" and "The Waterbending Master" (They're the ones Katara stole the scroll from). The traveling musicians are from "The Cave of Two Lovers. The prisoners of war likely refer to the Kyoshi Warriors, the men of the Southern Water Tribe, and possibly Bumi and the other citizens of Omashu.