Example of a project I'm working on to play with fonts in DrRacket. The environment of DrRacket is nice because we can immediately display the fonts in the REPL (for example as a result of a transformation). This can be useful for teaching (I think).
In this video I load two UFO fonts (Adobe Source Sans (https://github.com/adobe/source-sans-pro), then I add, subtract, multiply the fonts (using the idea of 'font math', like here: http://code.typesupply.com/wiki/FontMath).
I will publish the code as soon as I can :)