In order to raise money for the 17 million kids in Vietnam who do not have access to safe and clean water, UNICEF placed these "wells" around bars, clubs, and restaurants in the wealthier sections of Vietnam. The wells are extremely creative in connecting the visual aspect of this fundraising campaign with the cause at hand because the water level rises in the container as coins are dropped into it, therefore symbolizing the increase in opportunity to provide clean water to the citizens of that country and around the world.
This campaign is part of a United Nations initiative called Millennium Development Goal, which plans to cut in half the number of individuals who lack access to safe water and basic sanitation by the year 2015.
This is an excellent example of a promotional bank or container that fits the cause at hand. Always remember that the best marketing campaigns--especially guerrilla ones--are specific to the cause, brand, or event and draw positive attention to it through the marketing initiatives. In this respect, UNICEF was indeed successful.