Some Brooklyn students are taking advantage of a free program offered on the weekends.The first of six free SAT prep sessions began Saturday at the Brooklyn Historical Society. The history class is just one of three programs offered by the Gilder Institute of American History. Organizers say about 62 students registered for this pilot program. They expect to offer three new classes in the fall. Parents say it?s a great opportunity for students to stay engaged and be productive with their free time.