(Sample link) NASA for middle-school students http://www.nasa.gov/audience/forstudents/5-8/features/index.html
(Sample link) National Geographic for Kids http://www.nationalgeographic.com/kids/
NASA Astronomy Picture of the Day http://www.antwrp.gsfc.nasa.gov/apod/astropix
Earth Science Picture of the Day http://www.epod.usra.edu
Space Weather http://www.spaceweather.com
Daily science news and discoveries http://www.sciencedaily.com
Science Fair help http://www.sciencebuddies.org
you will need the streaming login to play the game space game