Five-Seven-Five Society

The 5-7-5 Society was an organization of young women who specialized in the art of poetry, with a focus on traditional haiku. Taught by the strict and disciplined Madame Macmu-Ling, only the wealthy young ladies of the upper echelon of families in Ba Sing Se were allowed to join the group. The society even has a guard who threw out people unworthy of the art. They had poetry meetings, in which haikus were recited by each member. In addition to practicing haiku, the girls also enjoyed tea parties, garden parties, and plain old parties.

History
When listening to the poetry through a window, Sokka was accidentally kicked through the window by an unruly ostrich horse onto the stage. He apologized, accidentally speaking in haiku form which impressed the young ladies, but irritated Madame Macmu-Ling. Sokka further impressed the group by throwing out a few more witty haiku, outdoing Madame Macmu-Ling herself. Becoming arrogant, Sokka mistakenly added a sixth syllable to the final line of his last haiku, causing a guard to quickly throw him out of the building.

Trivia

 * Madame Macmu-Ling is named after episode writer Lauren MacMullan.