SUMMER SAYS GIVE Watch a video of Summer Rayne Oakes telling you to donate to Grist. It's a strange scene: a sexy fashion model in skintight jeans, belly showing, telling a bunch of teenagers, "I studied sewage sludge and absolutely loved it!" Twenty-two-year-old Summer Rayne Oakes then confesses a fondness for bugs. From behind their desks, the students giggle and groan. The Fashion Institute of Technology in New York City runs a high-school program for aspiring designers. Today, Oakes is the guest lecturer. Summer Rayne Oakes. Photo: Lois Anshus The raven-haired beauty and self-described "eco-style expert" goes on to discuss …