Here are some good links that will provide your child with opportunities to get additional practice with school concepts as well as help them develop their independent critical thinking skills.
Literacy...
Create Your Own Animal Story http://www.kids-space.org/HPT/1a/11a.html
Flip A Chip http://www.readwritethink.org/materials/flip/
Funbrain Games http://www.funbrain.com/kidscenter.html
Spell Check http://www.funbrain.com/spell/index.html
Spin and Spell http://www.spinandspell.com
Story It http://www.storyit.com/
What in the World? (the eyes have it!) http://www.nationalgeographic.com/ngkids/what/what2.html
Young Writers Workshop Picture Prompt Practice http://www.meddybemps.com/9.700.html
Math & Literacy Printables http://ettc.lrhsd.org/archives/drill.shtml
Math...
AAA Math - Second Grade Math Lessons http://www.aaamath.com/grade2.html
Create a Graph http://nces.ed.gov/nceskids/Graphing/
Patterns http://www.arcytech.org/java/patterns/patterns_j.shtml
Tangram http://enchantedmind.com/puzzles/tangram/tangram.html
Tangrams Too http://teams.lacoe.edu/documentation/classrooms/
Visual Fractions/Find Grampy/NumberLine Game http://www.visualfractions.com/index.htm
Other...
Switcheroo Zoo http://www.switcheroozoo.com/
National Geographic Kids http://kids.nationalgeographic.com/
Pics4Learning http://pics.tech4learning.com/