Video: Processing is a programming language that allows people to make visual art (amongst other things) using programming and recently it released a version that works on the Raspberry Pi. Adafruit put together a guide for getting it on the Pi and working with their touch screen.
This project works on a few levels. First off, it serves as a nice introduction to Processing, which a fantastic entry point for people who are new to programming. Second, it shows you how to create a cool little interactive display that looks a lot like a miniature art exhibit. You can even hook the Pi up to a breadboard to control various lights and colours. Head over to Adafruit for the full guide.
Processing on the Raspberry Pi and PiTFT [Adafruit]