Learn to program in C++

http://www.learncpp.com/

Free Crochet Lessons

http://www.craftyminx.com/crochet-school/

Complete online homeschool curriculum, K-8

There are also high school lessons here:

http://allinonehomeschool.wordpress.com/

Very similar to Learning Lynx Classroom, but not specifically geared toward gifted students.

Tour of the International Space Station

This is a very cool tour of the International Space Station.

How Books Were Made (copperplate printing)

http://www.theatlantic.com/video/index/267036/#.UPTh0qJPNSM.email

Video of bookmaking machines from the 1940s.

Onomatopoeia

Everywhere around the world, people try to explain sounds. We all have words for what a mouse says, what a rooster says, what an ambulance says.

This site has recordings of children from all over the world, making the sounds for things--trains, animals, ambulances, etc.

http://www.bzzzpeek.com/

It's really fun to hear what native speakers in many different languages say that roosters say. And mice.

Great, fun site.