These are some good sites for third graders. White House for Kid http://www.whitehouse.gov/kids/whlife/index.html
National Geographic for Kids http://www.nationalgeographic.com/kids/
Fun activities - by girls....for girls. http://www.missoandfriends.com/
Math activities from Saxon textbook publishers. http://www.SaxonMath.com/Activities
a http://www.unitedstreaming.com