http://www.brainpop.com is an educational entertainment site with little games and short animated videos, etc. They've got lots of topics to choose from. The catch is that if you play more than 2 per day, you need to pay their annual subscription fee - can't remember what it is since we have not yet subscribed. But we've played around a little on the site and it looks fun for elementary aged kids.
I have been impressed with BBC's online activities for kids - I remember when Sam was really into solar system stuff, he loved playing in the space part of their site. They had activities like matching the planets to the right spot in the solar system, etc. You might just visit and see if you like it - it's all free. Here is a link to the space part that Sam liked:
http://www.bbc.co.uk/science/space/p...w/jigsaw.shtml
and a link to BBC's "evolution game", another one Sam liked:
http://www.bbc.co.uk/beasts/evolutio...ion_game.shtml
We have a few computer CDs as well, but Sam plays on the PC only about once every week or two - not too often. Some of his favorite CDs are "I am a dinosaur hunter" (simulates a dig, quizzes on where/when dinosaurs lived, how the various dinosaurs are related to modern animals, etc.), and "Infinity City" which has games related to math for all levels of ability, from simple counting to making change in a store, etc. [side note: Sam likes that Infinity City is set in an urban environment which is similar to where we live, as opposed to most media which looks very suburban.]
HTH a little...waiting to see what others like.
Tara