I have a little toy over on the right side of the blog that lets you "paint" a canvas. You'll see it over there where there's a blank spot. Run your cursor over the blank spot, and you'll see what I mean. Click to change colors, use your space bar to get a fresh canvas. The widget is a "Pollack Painter", after the artist Jackson Pollack. Two of the paintings I've made with it are shown here. Give it a try, and see what you can do with it. There's no way to save your masterpiece, but you can take a screenshot. PrintKey2000 is a great little program that lets you easily save your screenshots.
Let me know if you enjoy the toy, and if you'd like for me to feature some of your masterpieces.