This is a project for the EnergyHack (http://energyhack.de/). It polls the current energy consumption from a Volkszaehler energy meter. Depending on the consumption it controls an Arduino that controls two RGB-LEDs and a small air pump. The air goes into a water container where it bubbles up. The more energy you consume the more bubbles are produced.
At the same time the script uses an online text to speech service to speak the current consumption in the voice of Yoda from Star-Wars. In our hardware prototype the bubbles come out of a 3D-printed Yoda bust.