These students were participating in Earthcast - a production of the Earthbridges community of the Worldbridges network. More information about their annual celebration of Earthday is available at Earthcast Wiki.
There is no surer mark of a well-bred man or woman than proper and dignified conduct in public. The truly polite are always quiet, unobtrusive, considerate of others, and careful to avoid all manifestations of superiority or elegance. Twentieth Century Culture and Deportment, 1899