The Wolfram Machine project is an effort to create a set of documentation and useful modules (both hardware and software) for a computing architecture based on the mathematical theories presented in Steven Wolfram's book _A_New_Kind_of_Science_.
The MP4Free project provides a simulation, analysis and exploration platform for multi-processor system-on-chip applications at variable level of abstraction, providing also a comprehensive component library.
A small, portable, client/server GUI designed to work on many types of hardware, including handheld computers and other embedded systems. For more information and downloads, see http://picogui.org