This site comes from a history teacher in Michigan, and has a free online world history textbook. It's visually interesting, and appealing to jr. high and high school level students. The site seems to be under development, and some links aren't working as of this writing. Definitely worth keeping an eye on this improving resource!
Saturday Grab Bag
Printable curriculum materials for preschool through second grade levels.
Thursday History/Social Studies
This website from the Government Publishing Office has resources for learning about the US govern
The name of this site says it all!
Tuesday Language Arts
This company provides programs for beginning reading and math learning.
This company publishes three books for helping elementary learners explore science.
Self-paced, online courses for learning coding.