GeoGebra is a free software package
combining dynamic geometry, algebra and calculus. You can use it in a
lab environment, or for teacherled classroom demonstrations. It
can be used as a standalone system, or you can create interactive web
pages for student exploration outside of class. Try out its
interactive features in the Riemann sum miniapplet at the right, or by clicking on the following links:
Are you sold? Can't wait to start
creating your own applets? Click here for links to
additional resources, and for copies of the files we used in our
presentation. 
