Math Fact strategies http://www.mathfactscafe.com
math practice, games, flash cards, work sheets, brain teasers http://www.mrsdingman.homestead.com/MathLinks.html
Spelling practice http://www.spellingcity.com/
plate tectonics http://discoverourearth.org/student/tectonics/continental_drift.html
various language skill practice http://www.internet4classrooms.com/skills_3rd_lang.htm
Various Math skill practice http://internet4classrooms.com/skills_3rd_math.htm
Reading and math practice http://www.mdk12.org/assessments/k_8/sample_grade3_reading.html