I wrote a program in processing that reacts to how vigorously you shake an accelerometer.
The arduino communicates the sensor's readings through a serial connection to processing. I used a smoothing function, in my arduino code, to get clean values from the accelerometer, which tends to give very eradict readings otherwise.
Leaving the sensor alone for 10 seconds let's the storm go away, returning you to a clear day.
Download Processing and Arduino code