Here's a really fun and useful hack.
The program Dynadraw implements a dynamic drawing technique that applies a simple filter to mouse positions. Here the brush is modeled as a physical object with mass, velocity and friction. The mouse pulls on the brush with a synthetic rubber band. By changing the amount of friction and mass, various kinds of strokes can be made. This kind of dynamic filtering makes it easy to create smooth, consistent calligraphic strokes.
The C source for the dynadraw demo program is available. You can save this onto your IRIS, compile it, and give it a try. If you're a Mac or PC hacker, you might be able to port this program easily to your own platform.