The National Gallery of Art in Washington D.C. has a very nice website, well worth exploring. There's a kids page on which I found this neat Collage Machine. It's very easy to use; if you're truly lazy, just click on the "Auto" button at the bottom and create a random (but still editable) image, like the one at right. I think it'd be an ideal way to generate sidebar art for a bl0g. But that's just me. There's no capability to save or print it, so you'd have to do an Alt-Print Screen and paste it into a paint program.
Speaking of which, ArtRage is a free painting program. It doesn't have the full editing and image manipulation tools of Photoshop or Paint Shop Pro, but that's the way the designers intended it:
ArtRage was designed to work like a painting simulation rather than a standard digital painting application. While there were some difficult decisions that went in to the design, the eventual result reflects what we wanted to do with the app, which was reflect real world painting tools.ArtRage is meant to be a canvas, with some tools. It�s meant for playing around with paint, experimenting and exploring, and ultimately having fun. We certainly didn�t intend it as a replacement for any other package, and that decision let us make some pretty important changes to the workflow that helped the package become accessible to anyone. At the same time, those changes also removed some tools that were inappropriate to the package but may have been expected by some users.
The picture on the left is a good example of what it can do. Click here for full-size. (You can use a mouse to draw; but if you have one, a graphics tablet is ideal.)
Windows and Mac downloads here.