"Safe Places to Play"
Websites for kids - hosted and sponsored by different federal agencies

Maestro Learning
Educational software, apps, and activities

MIT Hacks
College student fun - often in an educational way!

Make
"MAKE unites, inspires, informs, and entertains a growing community of resourceful people who undertake amazing projects in their backyards, basements, and garages... The MAKE audience continues to be a growing culture and community that believes in bettering ourselves, our environment, our educational system—our entire world." 

Science News for Kids
"Science News for Kids was launched in 2003 by Society for Science & the Public (SSP) as a youth edition and companion to the Society’s Science News magazine.
"... the Society advances the popular understanding of science through publications and educational competitions and programs. Its mission is to promote the understanding and appreciation of science and the vital role it plays in human advancement: to inform, educate, and inspire."

The Happiness Project
"On her popular blog, The Happiness Project, [Gretchen Rubin] reports on her daily adventures in the pursuit of happiness."

Wikipedia Education Foundation
"The Wikipedia Education Program's vision is to mobilize and empower the next generation of human-knowledge generators to contribute to Wikimedia projects. 
"Professors who participate in our program assign their students to edit Wikipedia articles as part of their coursework. Students are assisted by trained Wikipedia Ambassadors, who help both in the class and on wiki."