iCivics - iCivics exists to engage students in meaningful civic learning. They provide teachers well-written, inventive, and free resources that enhance your practice and inspire your classrooms.
Edward M. Kennedy Institute - Newly opened in Boston, this institute aims to be the ultimate destination for civic learning and engagement. Offering a wide variety of virtual programs and interactive lessons in social studies for all ages.
Atlas Obscura - Students can “travel” the world without leaving their homes. Atlas Obscura is a definitive guide to the world’s hidden wonders.
EDSITEment - Partnership between the National Endowment for the Humanities and the National Trust for the Humanities and offers free high-quality humanities education materials in the subject areas of history and social studies, literature and language arts, foreign languages, arts, and culture.
CIA's The World Factbook - Yes, that CIA. They have compiled a very detailed database of basic intelligence on the history, people, government, economy, energy, geography, environment, communications, transportation, military, terrorism, and transnational issues for 266 world entities.
CIA's Spy Kids - Learn about the CIA with kid-friendly language, classroom activities, and online challenge games.
TPSP Tasks for 5-8 - TPSP = Texas Performance Standards Projects. This link will take you directly to the high school grade band. From there, choose your subject and explore all the projects they have to offer. Keep in mind, these projects are intended to take weeks to months to complete and follow the complete research and presentation cycle.
National Geographic - Lesson extensions and research projects with real world applications.
Byrdseed Social Studies - Common social studies projects are given updates to allow students to dive deeper into more complex concepts.
Social Studies Songs - Collection of songs to helps students learn social studies concepts.
Oregon Trail - Classic Oregon Trail game that has made its way into current pop culture. Don't die of dysentery!
Ducksters - Quick information (short articles & infographics) about so many history and social studies concepts.