Osprey posted this fabulous drawing site, and I did a drawing of my computer desk, the area between my keyboard and the monitor. It was fun and interesting to see what it put in when I scrubbed the mouse across an open space in "sketchy" mode (light grey surface of desk). Left-click on the drawing to see a much larger view of it (nice to see the details).
If you visit, don't be surprised that it is a blank white screen with just a few menus on the top. Just start drawing with your mouse and play with it!