Games To "WORK" on the Computer

Do you let your youngest work or play on the computer.  In our house we have to be careful what we say about the computer.  If we say "play" then the kids do not treat the computer (my laptop) with respect. If I say "work" then they know it might be fun but we still need to be careful cause Mommy uses her computer for work and work is serious business.

What programs or sites do you use for your kids to "work" on? We use many different sites for "work" in our house but LearningGamesForKids.com is one of our favorite. We love that we can find preschool games, keyboarding games, social studies (also known as history) games, even science games. There is so many games for learning on this website.
Share one of your favorite sites to have your children "work" on. I would love to check them out.