Detroit's troubled school system remains in emergency management, its enrollment dwindling and its labor-management relations contentious. Yet in spite of those challenges, a school there is making a bid to innovate with many of the formal structures that have long guided not just teachers' roles, but also how students are organized in classes. At Palmer Park Preparatory Academy, teachers are gradually assuming administrative duties to become the city's first teacher-led school. An extended day, part of the district's reform policy, gives the staff time every afternoon to compare teaching strategies. A new, pilot schedule for 7th and 8th graders lets teachers regroup the middle school students in different English/language arts and math classes frequently, based on the students' performance and how quickly they are learning new material. The changes are the K-8 school's attempt to get concrete about the much-touted but often vague concept of "differentiated instruction" for students, especially for those who have struggled to grasp key concepts and risk falling further behind. They are also the product of a partnership among teachers, the local teachers' union, the central administration, and Houghton Mifflin Harcourt, the educational publisher hired in fall 2009 to revamp Detroit's curriculum. In a sense, the 650-student school is also an incubator of several ideas that in recent months have caught renewed attention from education reformers around the country, including: (1) the notion of the teacher-led school; (2) extended school hours, a concept favored by the Obama administration; and (3) on-the-job professional development based on data analysis. While still in its infancy, the school is being praised by district leaders as an example of organic reform.