Straight from the Web

 

Mathematics
Math Maven Mysteries
http://teacher.scholastic.com/maven/index.htm
      Worksheet
 

Social Studies
50 States.com
http://www.50states.com
      Worksheet
      Worksheet
 

Science
Creature World
http://www.pbs.org/kratts/world/index.html
      Worksheet
 

Language Arts
Mystery Net-Kids Mysteries
http://mysterynet.com/kids/
      Worksheet