This is a site developed by the U.S. Department of Education. On this site you can find teachers sharing teaching strategies in all content areas and grade levels, reports and research on efforts to improve teacher quality and learning, and a toolkit of best practices in professional development.
This site has workshops and courses that educators can for professional development with all subjects. You can do these workshops/courses for graduate credit, for yourself, or study with a group. Also on this site you can find lesson plans, interactive activities you can use within your classroom, and blogs about different educational things.
The website provide teachers with information about workshops, courses, distance learning, and lesson plans. The website have different resources for the teachers depending in the discipline and grade level.