Wikipedia, the open source encyclopedia is a resource I really love. Mostly it’s just hard to avoid letting it take you to a random page and reading. Actually I think encyclopedias are one of the great self-teaching tools for young kids. I recall stories from both Borges and Feynman about devouring encyclopedias as small children.
Now, via Michael Nielsen’s blog, I learn that in addition to all the other wiki(insert word here) there is Wikibooks a collection of free open-content textbooks. So far some of the textbooks are pretty incomplete, but definitely a cool site to watch grow.
O brave new quantum world!
Apparently Bill Gates read a whole encyclopedia by the age of 10, so it can turn you into a Nobel Prize winner or a billionaire, whichever you prefer.