DH wants to do a unit on economics with the boys. He'd tried a commercial workbook which turned out to be deadly dull, so these are some other resources for economics for kids.
James Madison University offers online lesson plans for teachers in elementary, middle and high schools.
More online lesson plans from the University of Nebraska at Omaha (my mother's alma mater) done in a nice little table laying out concepts learned, content area and NE and US standards addressed. Some of the lesson plans include food such as M&Ms and popcorn!
The National Council of Economics Education publishes a number of books on basic economics, personal finance , entrepreneurship, and business.
Finally, The Stock Market Game is designed for classroom teachers to allow each student to "invest" and track stocks. The money is virtual but the stocks are real. Kids get to research, pick and trade stocks, just like the real thing! Kids compete to have the wealthiest portfolio against their classmates, and other kids on the regional or national level. Game dates for the 2006-07 school year can be found here.