"The National Library of Virtual Manipulatives" (Software package promoted for sale, but they also have a free version. Very nice site chock full of online applets and manipulatives for teaching math concepts to students of all ages. ALL the online manipulatives – and there are HUNDREDS of them – are free. http://nlvm.usu.edu/en/nav/vlibrary.html
Digital History University of Houston has #homeschool history assignments, projects, primary source documents, textbook, an options for "light" or "in depth" study. Free, but the worldview may not fit all families.
Here you will find over maps representing many different time periods. A friendly license allows teachers and students to use up to 25 maps in non-commercial school projects without further permission.