I love that the statistics reported for numerical questions includes the mean, median, standard deviation, and quartile cutoffs.

What would make it even more awesome would be to provide a visual representation of that, for example through use of a boxplot (see http://www.physics.csbsju.edu/stats/box2.html or http://en.wikipedia.org/wiki/Box_plot). Ideally, multiple numerical questions would be presented as a single boxplot with each sub-question charted.

Single numerical questions might be presented either as a histogram (http://en.wikipedia.org/wiki/Histogram) or as a probability density function (http://en.wikipedia.org/wiki/Probability_density_function).

I can't say what would go into programming this but it sounds like a fun project, doesn't it?