Dan Shiffman is an incredible programmer, artist, and teacher. He is one of the developers behind Processing and has also build a few useful libraries including the Most Pixels Ever library which allows a Processing application to run on multiple screens. His SMS library allows Processing to gather data from an Apple Macbook’s sudden motion sensor. This little gyroscope is normally used to stop the hard drive if the computer is dropped, but it could be re-purposed for just about anything.
I owe a lot to Dan as his tutorials and example scripts have been a huge help to me as I’ve been learning Processing. If you’re new to the language I highly recommend all the resources he has on his site. He also has a great book on learning processing and plenty of online examples to go with it.