Parallax has an interesting kit called the M-Sorter. It really sorts M&M candies, and even Skittles. The device is incredible and ingenious in it's simplicity and design, in that the whole project runs with only 1 moving part! In fact, the only devices needed to make this project work are the TAOS TCS230 Color Sensor (Available from Parallax with the kit), and a standard hobby servo (included in the kit).
This kit demonstrates some of the principles found in everyday industrial applications, and shows that the BS2 is a very capable contender in this area, as well as being just plain fun to watch!
The photo above shows our unit in operation. Yes, that is a BOE-Bot in the back giving it a jump (power)! As you can see, the only 2 connections that are needed to the BS2 (Mounted on a Board Of Education) are to the servo and to the TAOS Color Sensor. Operation is pretty smooth. Of course I did have a few deformed M&M's that hindered the operation temporarily, but they have been removed. Our new M&M's slogan is, "M&M's, they melt in your mouth, not in your M-Sorter!"