Problems in Microeconomics

This site, by Byron Brown of Michigan State, uses Excel 5.0 or higher as a teaching device for micro courses (generally for principles students). The 25 exercises come in two modes: "practice" and "test" (in the latter, each student faces a different set of numbers in the problems). Each set of exercises comes with instructions, and the code for the spreadsheets is encrypted.

http://www.msu.edu/course/ec/201/brown/pim/