Jason and I have released the source code for Quixo3D at http://codeplex.com/Quixo3D. In addition to the source code is a zip file with the first release.
We've been wanting to release this project for some time, ever since the last Twin Cities Code Camp, but we wanted to wait for VS 2008 to release. VS 2008 is finally out, and Jason took the initiative to convert our code to a VS 2008 project.
Now that the code is under source control, I'm actually eager to dive in again and make some improvements to the UI. It's actually very discouraging to work on code (with multiple developers) when there is no source control.