FreeRice.com
http://www.freerice.com/

For each answer you get right we donate 10 grains of rice through the UN World Food Program to end world hunger.
WARNING: This game may make you smarter.

Glencoe Multilingual Glossary for Social Studies
http://www.glencoe.com/sec/socialstudies/mlg/mlg.php?site=6

Glossary of Grammatical Terms [Wilfrid Laurier University]

http://info.wlu.ca/~wwwml/LangSem/definitions-sorted.htm

Holt,Rinehart and Winston Multilingual Glossary for Math
http://my.hrw.com/math06_07/nsmedia/tools/glossary/aga/glossary.html

Holt, Rinehart and Winston Fab Vocab for General Vocabulary

http://go.hrw.com/eolang/wordwatch/benign/benign.htm

Discover the facts and stories behind some everyday words

McGraw-Hill Multilingual High School Glossary for Science
http://www.glencoe.com/sec/science/mlg/mlg.php?site=20