I felt like making an audio project as my first attempt at hacking something together using the Arduino, and I had some spare parts lying around from the Machine Project class, so I decided to make a better squarewave synth. This one steps up and down, so it's arpeggiated, and makes some pretty awesome sounds, a la Pacman and Excite Bike. I ordered a ton of electronic parts and sensors from Jameco, can't wait to build more stuff!