One Young World
One Young World is, "The premier global forum for young people of leadership calibre. It manifests the reality of common humanity and the shared existence of all the peoples in one world, Its purpose is to connect and bring together the youngest, brightest and best and to ensure that their concerns, opinions and solutions are heard."
Here are some of their ads. Quite good (and quite embarrassing to world leaders. Or the world, come to think of it).