Penguin sledding is a recreational activity in which a person sleds down snow- or ice-covered surfaces on the back of an otter penguin. The riders usually lure these animals to them using fish. Though the game is typically played by young children, it can be enjoyed by any person light enough to ride the animal.
When Aang was freed from the iceberg, he immediately asked Katara to go penguin sledding with him, something to which she confusedly agreed. However, when it came to catching one of these animals, the Avatar's method of chasing them proved to be ineffective, as the animals evaded capture each time. Katara came to his aid by showing him how to lure them with fish. She threw the bait to Aang, who was immediately overrun by the hungry animals. Using that technique, Aang and Katara each managed to catch an animal, enabling them to go penguin sledding.
As they proceeded down the slope, they encountered ramps and ice tunnels, both of which they traversed while on the backs of the otter penguins. At one point, Aang even used airbending to increase the his speed. Their ride unintentionally brought them to the site of an old, abandoned shipwreck.