Google Code University is a collection of free courses on computer science.

There is no registration and all materials are free to use. There are courses on programming languages, web programming, systems and more. There are basic tutorials and advanced classes. Some of the materials are from actual college computer science courses.

This is a great resource for computer science classes and can be used in class or as extra reinforcement.

101 Science is an incredible site with a huge amount of resources for science.

The site has more resources than I could count, organized by topics such as "electronics", "chemistry", "biology", "physics", "math" and "photography." There are also resources for earth science, astronomy, robotics, ethics, java applets, and much more. Each main category has sub categories also.

Each topic has scores of links and resources, including articles, web sites, and videos. Some videos are from MIT, TED and more.

If you teach science, are a student of science, or just like science, this is a must see site.

Here's a look at the main Physics page:



Each link on this page has more links. Here is the page on Gravity:



(Some sub categories have much more than this even!)


This site is just tremendous with over 20,000 links and resources.