Stephen Downes

Scratch is "a new programming language that makes it easy to create your own interactive stories, animations, games, music, and art -- and share your creations on the web. Scratch is designed to help young people (ages 8 and up) develop 21st century learning skills." Available from MIT's Media Lab, there are Mac and Windows downloads. They are working on a Linux version. This post from Quentin D'Souza links to a bunch of Scratch resources.