Lego Machines
This is a one-pixel scanning digital camera, made completely out of Lego. It uses a little Lego magnifying glass for a lens. It uses VisualBasic code to load readings into an Excel spreadsheet, and those can be converted into an image. I almost won Lego's monthly model contest with this. I should have posted a better picture. More pictures and the code are HERE.
I have made many more things, including an Etch-A-Sketch plotter, a pen plotter, a card sorter, a line-follower, and more. I'll look for photos.
A webcam robot with web control UI
CNC Etch-a-sketch
Card sorter that unmixes red and blue playing cards
Device that lets the RCX drive real stepper motors, for when you need the power and control.
A pan/tilt webcam and computer interface that lets you remote control it over the web.
A super mini line-following robot that only uses one motor.