Find the best educational sites for virtually any subject. The sites listed here provide substantial learning materials and are often free, but they require more discipline than Online Classes because the guidance is not as strict - only some offer assessments, and there are no scheduled classes or deadlines. Some of these educational sites are intended to be used as a reference or a supplement to a textbook to help learn specific topics rather than as a standalone learning tool. Some sites, particularly those for younger students, include free educational games.