Camille Mahlknecht, 9, has some big fun planned for this weekend．She and other residents of Agoura Hills, California, plan to pick up trash during their city’s annual cleanup．At the same time, Wissam Raed, 12, will be busy volunteering too．Thousands of miles away in Lebanon, Wissam plans to put on a play at an orphanage and bring potted plants to elderly people at a senior citizen center． Some other children like Nathan White, 10, have personal reasons for volunteering．Nathan’s grandmother died of a heart attack．To help raise money for medical research, Nathan part