At one point in my college career I learned a little bit of Processing, which is a simple and very beginner friendly scripting environment for creation of visuals. I learned the fundamentals, but never really got around to using these fundamentals. Rather than let that go to waste, I've decided to be more proactive about writing up little scripts or "sketches" as they're called in the world of processing.
Much like when I actually sketch, I didn't really have an idea in mind at the outset. To start out I'd refresh my memory by simply drawing a line from the center of the screen to the mouse location. Once that was working, I knew that next I wanted to be able to click and draw a new line. This turned out to be a perfect exercise in Arrays, which I used to store the X & Y locations from the previous 100 mouse clicks. There was an unintended outcome: if you hold down the mouse the lines are short enough that rather than lines, they appear as a drawing rather than "hardlines." Also, the 100 point memory bank I built into the array runs out much quicker when holding down the mouse, so in a sense the drawing "unravels" itself while you draw it.