NASA for high school students http://www.nasa.gov/audience/forstudents/9-12/features/index.html
Meet some NASA women! http://quest.arc.nasa.gov/space/frontiers/profiles.html
National Mole Day Foundation http://www.moleday.org
Science Olympiad http://www.soinc.org
The top two percent http://www.us.mensa.org
An interactive periodic table -- just what everyone needs! http://www.chemicool.com
Can you solve the SAT question of the day? http://www.collegeboard.com/apps/qotd/question
Environmental Protection Agency http://www.epa.gov