OpenCulture - courses

http://www.openculture.com/freeonlinecourses

AAA Math

http://www.aaamath.com/B/index.htm

Study site for K-8th grade with a Spanish version.

Subjects Covered:
K-8th grade math topics up to geometry and algebra
Spelling
Vocabulary
States of the USA
World Nations

Features:
Interactive practice with games and pictures
Customizable spelling and vocabulary lists (1st-8th grade)
Math articles
Flags, capitals, states, and nations worksheets and exercises