Ohaus (Tet your ability with a triple beam balance) - http://www.ohaus.com/products/education/weblab/TBBread.html
Flashearth (Latest and greatest way to see your house from the air) - http://www.flashearth.com/
Earthscience picture of the day (EPOD) - http://epod.usra.edu/
Astronomy Picture of the day (APOD) - http://antwrp.gsfc.nasa.gov/apod/astropix.html
Hubble Deep Field Image (This will humble you) - http://hubblesite.org/hubble_discoveries/hubble_deep_field/
Earth Science Review Games - http://sciencereviewgames.com/srg/subjects/es.php
Top Earth Science Review Links - http://reviewearthscience.com/subjects/es/review/top-sites.php
Constellation Info - http://www.dibonsmith.com/constel.htm
World Sunlight Map - http://www.die.net/earth/