Limor of Adafruit Industries posted this video demonstrating how the Waveshield kit can turn Arduino into a sample-bending audio tool.
Consider for a moment that potentiometer replaced by – oh let’s say – photocells or maybe a force-sensing resistor. If you’ll excuse me – I’ve got some experimentation to go do – Wave Shield for Arduino
Related: Wave Shield kit for Arduino
In the Maker Shed: Arduino Diecimila