Make conductive rubber and use it to create a flexible touch sensitive robot skin. The resulting skin can be stretched across a frame or mounted on solid surfaces. It can also be mounted on curved surfaces or clothing.
Charliecube is a 4x4x4 tri-color LED Cube. But what makes it special? Other cubes use shift registers, decade counters, or other components to control all the LEDs and can cost upwards of $150. The charliecube can be run using only 16 digital pins with no extra components and costs $30 plus an arduino.