Four Seconds - A timer and a simple rule: stop it at exactly four seconds.
Math Games - Math Games is a website which kids in Preschool through 8th grade can practice math.
Cotrio - The most beautiful way to move your brain and imagination
GCompris - Educational Game for Children 2 to 10 years old.
Wikids - An encyclopedia that talks to your kids
childsplay - Childsplay is a collection of educational activities for young children and runs on Windows, OSX, and Linux. Childsplay can be used at home, kindergartens and pre-schools.