Augmented Reality Video Games - So an AR game is a game that draws objects over a live video feed of the world (usually with something like a head-mounted display or a phone). The effect makes it seem like there are 3D virtual objects in the real world. I worked on two such games with the smart and creative folks in Blair MacIntyre's AR games studio .
This project wasn't just me: it's part of ongoing work that many folks, especially Richard Shemaka are doing in the lab.
Fractals - I coded a fractal generator in Java. It's designed so you can build the fractals with a Xbox360 video game controller (or a keyboard and mouse). You can see the latest version of the code here: http://code.google.com/p/fraccontrol/. Here's a sample fractal (of course in the actual software you can zoom in infinitely and see at the details):
Bluetooth Twiddler - Me and a team of 3 others built a functional hand-held Bluetooth keyboard and mouse. I designed the circut board myself.
Autogenerating stories - I took a class on interactive narrative by Brian Magerko. In the process I build a fairly crude system for generating stories about samurai based on user goals in prolog.
Scratch Programmable Fabric - a mini-project with extending the Scratch kid's programming environment to let you control fabric with leds. It utilizes a hilarious hack...the scratch application outputs a graphics file which is then converted by Jython into C that can be uploaded to the microcontroller.
Ruby USB - I once made a framework to communicate to USB Human Interface Devices devices in Ruby. Check out the video of me talking about the project first. Then visit the project webpage for the details and code.