Something for middle school science classes perhaps:

The Siemens Foundation, Discovery Education and the National Science Teachers Association (NSTA) have partnered on this unprecedented initiative to educate, empower and engage students, teachers and communities to become “Agents of Change” in improving their community. Student teams from sixth through eighth grade, under the mentorship of a teacher or adult supervisor, can register for the Siemens We Can Change the World Challenge at www.wecanchange.com.

One of the challenges with getting students involved with competitions is the question of does it really fit with the curriculum. From all appearances the partnership that includes the National Science Teachers Association and Discovery Education has worked pretty hard to align this program with national standards. And yes, there are prizes too

Top prizes will include a chance to appear on Discovery Network's Planet Green, a share in thousands of dollars in cash prizes, a one-in-a-lifetime Discovery Adventure trip and more.