CliffsNotes: The popular study tool is now online and most of their content is free. Search for the piece of literature you're studying to get overviews, character biographies, themes, and more. Don't use this as an excuse not to read the book!
Getty Museum: Explore the museum's collection by browsing through the medium, theme, or by artist. Short artist biographies and work descriptions add to each entry.
Tate Museum: Comment on works of art, play games, upload your own art to a gallery, and get ideas for art projects that you can do at home.
Google Cultural Institute: View art from collections around the world, zoom in to see the details, and compare works of art.
American History: This website includes biographies for almost 100 famous Americans, as well as biographies for some of America's most famous authors.
Biographical Dictionary: This is a large collection of biographies, for people all over the world. However, anyone can edit the content on this site, so make sure to double check things that you find here.
Countries and States
Stately Knowledge: Use the interactive map to click the state you want to learn about.
The World Factbook: Use the map to select the country you'd like to learn about, or use the dropdown list to select one alphabetically. Then, use the plus and minus buttons to expand the information tabs.
General Homework Help
Fact Monster: Find facts on thousands of subjects! Use the search bar or click a subject to explore.
Kids Click: A search engine created by librarians just for kids.
USGS Kids: Learn about science, animals, and their environment through games, stories, and fun projects.
eLearning for Kids: Click on your grade to find interactive activities that'll let you have fun while you learn.
Cool Math: Math for anyone ages 13 and up. Don't like math? Start with 'Math Survivial' to get over your fears!
Math Playground: Math games on just about any topic you can think of. Having trouble with linear equations? Play a game and improve your skills at the same time!
OLogy: A science extravaganza, curated by the American Museum of Natural History.Choose an -ology and learn, learn, learn!
Bill Nye's Home Demos: A collection of science demonstrations from the ambassador of science himself, Bill Nye. These can be the foundation of a science fair project, or just something fun to do on a Saturday afternoon.
National Geographic Kids: Games and articles about countries and animals from around the world.
Ben's Guide to US Government: Click your grade in Ben's kite and learn about the government: how it was formed and how it works today.
iCivics: Learn what it means to be a knowledgable and engaged citizen in a fun, colorful website.
The Constitution for Kids: Information about the one of the most important documents in American history.