So the Macbook pro is loaded with sensors like temperature, fanspeed, accelerometer, ambient light and a microphone. Most of these sensors are accessible from within Quartz Composer and VDMX but i've not yet seen somebody make use of the temperature, fanspeed and ambient-light sensors within the Macbook Pro. Wouldn't it be nice to make use of the temperature sensor to control the fx within VDMX or Quartz Composer?
Things i've run into so far that make fun use of the accelerometer and ambient light-sensor are little programs like Liquid Mac and Nightsounds.
Nightsounds is quite nice once darkness falls and your Macbook starts to make some cricket noises.
edit: just found this little application on my search:
http://episteme.arstechnica.com/eve/for ... 5001279731
it uses the backlit keyboard of the Macbook Pro to visualize the CPU-usage.