There are tons of TV and product (webkinz freaks me out) web games for kids, all of the PBS kids and Nickelodeon shows have their own interactive games, but they're loaded with ads and designed to build loyalty to the show. I'm cautious about letting Elliot do any computer games regardless of product placement, but we have slowly opened the gates to a few sites (with good user interface) that have met our approval.
Great for pre-k kids as well. Interactive games that promote early literacy and math skills.
Elliot's gym teacher told him about this site (nice viral marketing) that has animated movies and games about famous authors (we watched Roald Dahl), ancient history, science and math concepts. Comprehension quiz after the movie.
Read Write Think
Simple phonics, prefix and suffix alphabet games.
Australian site with some great math games that are easy to manipulate.