Not many know Severn Cullis-Suzuki, but she is one of the few bold environmental activists who have inspired many people across the globe. In 1992, at age 12, Cullis-Suzuki raised money with members of ECO to attend the Earth Summit in Rio de Janeiro. She delivered a very inspiring speech that not many children would dare to do.
Her video can be used in your classes in order to inspire your students to speak up, especially when the topic is related to the environment.
More about Severn Suzuki at http://en.wikipedia.org/wiki/Severn_Cullis-Suzuki