Benchprep — Online Test Prep
Benchprep is a comprehensive online test prep resource, providing reading and review materials, practice problems, and entire practice exams for dozens of standardized exams. Whatever standardized exam you are preparing for, they probably have it, from AP exams, college and graduate school admission exams, and licensing and civil service exams to prep courses on college subjects. A monthly or lifetime subscription gets you access to your preparation materials on the web or on your smartphone so you can study any time, anywhere.
SoftSchools.com — online games for elementary math and reading
Student of Fortune — crowd sourced learning
Student Questions — crowd sourced learning