They bill themselves as "the world's largest publisher of books for gifted children." It's a very homeschool-friendly company, partly because the materials promote the kind of higher-level thinking that many homeschoolers want to teach, and partly because they provide small volume packages and pricing. (Unlike the more public school oriented publishers!) Probably best known for the Michael Clay Thompson LA materials, which are one of my favorites! They also have math, philosophy and social studies books.
Online, interactive program for learning music reading and theory.
This non-profit organization offers over 100 free self-paced, online, college level courses.
This online math program is designed to help students with math problems (including dyscalculia.)
This hands-on grammar curriculum includes CD ROMs, teacher manuals, and games for learning gramma
Online, super-hero themed science games for elementary and middle school levels.
This program includes videos, worksheets and quizzes for history learning in jr.