San Francisco Symphony for Kids: Learn about music and instruments with the San Francisco Symphony. Joely absolutely loves this site!
Nourish Interactive: Nutrition education games for kids. Although this uses the "new" food pyramid (which I thoroughly despise), the information is great on this site, and the games are really engaging.
Make Your Own Handwriting Sheets: How cool to be able to make your own handwriting sheets! Type in the words your want you kids to practice and—voila!—a printable handwriting sheet. And there's lots of customizable features so it can "grow" with your kids.
My Grocery Deals: Peruse local grocery ads all at once, generate a shopping list based on the ads, and so much more. And it's free to use! I've heard that many people are turning to this instead of using the Grocery Game.
Wise Bread: Living large on a small budget. The name says it all.
Student New Daily: A great way to incorporate the study of current events with your middle school or high school student. There's even comprehension questions along with the news stories on the site.
Peanut Butter Munchies: Can you just say YUMM!?