Teaching

More personally, I have either used or am using the following in my teaching:

• Mathematica --- as steep as the learning curve is, you cannot deny how useful Mathematica can be in showing students powerful mathematics. While I have written notebooks to accompany the calculus sequence while at Berkeley, these days my focus is primarily using Mathematica for class presentations and programming exercises.
• MATLAB --- we have a lab outfitted with MATLAB and use it for a variety of courses. I've developed some software in MATLAB which I've found very helpful in teaching multivariable calculus (note: to use this software, both pieces must be downloaded and run in MATLAB. Also, the software takes input in a vectorized form for MATLAB, so there's no need to use periods after arithmetic operations to indicate coordinate-wise arithmetic.):
• graph3d.m graph3d.mat - graphs up to two functions of two variables and allows you to rotate the results in real time.
• congrad.m congrad.mat - given a function of two variables, gives a contour plot and plots the gradient field
• pcurve2d.m pcurve2d.mat - plots a parametric curve in two dimensions as well as velocity and acceleration vectors.  Will also plot a two dimensional vector field.
• pcurve3d.m pcurve3d.mat - the same as pcurve2d, except in three dimensions.  The resulting plots can be rotated in real time.
• psurface.m psurface.mat - will plot parametric surfaces in three dimensions and allow you to rotate them in real time.
• Dr. Annalisa Crannell's materials on writing in mathematics.  This is a very useful site, both for ideas on writing projects and how to grade a project once you've gotten it.
• The Galileo site at Harvard (galileo.harvard.edu) is a good resource for peer instruction and ConcepTests, including many of the tests I've written for multivariable calculus.