New York Times
http://www.nytimes.com/learning/teachers
Has daily lesson plans for grades 6-8 and 9-12, as well as daily news "snapshot" activities that can be developed into lesson plans for grades 3-5. These are based on current events and use interdisciplinary resources and activities. A particularly useful feature of the daily lesson plan is the information provided to identify academic content standards that can be addressed by each lesson.  Users can access the related academic standards for many individual states as well.