This is an interesting Google Earth interface by Jens Franke & Thomas Gläser. It utilizes and Arduino, foot switches, and overhead projector to navigate the Earth.

Arduino Earthwalk represents an intuitive way to control Google Earth. The user navigates on the earth´s surface using five footpads. The arrows represent the cardinal points as heading directions. Activation of one of the pads simultaneously with the center pad will speed up the pace of navigation. Simultaneous activation of the pads marked with plus or minus will result in zooming in and out respectively.

Learn more about Earthwalk [Google translated]