THIS FALL, when students at more traditional boarding schools return to blue blazers and lacrosse tryouts, 120 teenagers at the new Conserve School in remote Land O'Lakes, Wisconsin, will be honing their wilderness survival skills and learning to write alternative-energy proposals. Students on the $60-million campus will live in buildings that incorporate locally felled wood, compete dorm-against-dorm in water and electricity conservation, and pull all-nighters poring over paper-saving e-books. The enviro tyros will hike, bike, and paddle on 1,200 pine- and maple-wooded acres, eat organic buffet meals, and sleep late. (In harmony with adolescent biorhythms, classes don't start before ten o'clock.) But the school is more than just a $25,000-a-year summer camp: Students will contend with a full slate of physics, calculus, and Plato. After all, most Conserve graduates will be expected to log a few years in the Ivy League before getting their chance to save the world.