Don't buy it: Get media smart!

www.pbskids.org/dontbuyit

This site from PBSkids.org teaches kids about media literacy while encouraging them to be critical of advertizing and marketing. Activities like the "design your own cereal box" walk users through some of the psychology behind product design for children so kids learn to see some popular ad tricks and gimmicks.

The Elegant Universe

www.pbs.org/wgbh/nova/elegant/program.html

Not only is NOVA’s 3-hour program about string theory and quantum physics available to watch online for free, it’s also divided into chapters ranging from 4 to 10 minutes long so you can watch as much or as little as you like at once.

The Human Body & Mind

www.bbc.co.uk/science/humanbody

This site is full of interactive online activities, games and surveys that teach as well as entertain. Test your memory and your individual senses, or learn about almost anything having to do with your "mind" or "body" by following the appropriate links.

Mango Languages

www.mangolanguages.com

As the "first free enterprise language learning course available on the Internet", Mango offers online tutorials to learn conversational basics of about 10 languages. Listen to audio samples, and follow along with the prompts and on-screen tips.