Code.org - Computer coding using visual blocks, with links and resources to other programming languages. Sponsors Hour of Code.
NASA for Students
SciStarter - Citizen science projects you can join! Search for projects based on activity or topic.
Science Buddies - Activities, experiments, and projects for both science and engineering.
Science News for Students - Award winning and age appropriate journalism.
Scratch - Computer coding using visual blocks.
The Cosmic Calendar - National Geographic video and Discovery Education
The Planetary Society Kids page