uGNU/RTOS (literally "micro G'Noo RTOS") is an Open Source serial Real Time OS for microcontrollers (PIC, ATMEL).
A Development Framework for Coldfire
Contains a framework for Coldfire MCUs like 52254. The framework supports a Command Line Interface (CLI) that may work from Serial port, USB or ENET. The framework uses Processor Expert and IDE requirement is MCU Eclipse 10.4 from Freescale. Includes the FunkOS Realtime Operating System by Funkenstein Software Consulting, available at http://funkos.sourceforge.net Mainly it is a support package for the development board Perseus, but I have ported also the RTOS to MCF52233DEMO board. More to come....
A (new), Distributed and Supercomuting ready, Component Oriented Opperating System, together with a (special) toolchain to build it. (It will run on I386 networked machines initially)
The future of information technology will be based on controlling the flow of natural light. This project is an attempt to establish the code (or software) that will enable this to happen. It involves rewriting an OS from the ground up.
The Harmony project has two fundamental guidelines: Make it easy and make it flexible. It is an entirely new operating system that focuses on giving the user a totally customizable experience.
An ASCII MMORPG / World Simulation / Genetic Programming Project
This project was previously oriented towards creating an AI based Operating System. However new visitors should refer to www.theasciiproject.com for information about what this project has developed into.
Maiden-core is a Linux kernel robotics API module, extensible in Erc. The Maiden Project also documents and develops the Maiden architecture for mobile robots, a set of (optional) designs and standards for robots using the Maiden-core API.
lysis is working on a features rich home automation system that ranges from CAN-bus, 1-wire and RF up to a HTPC; both hardware and software are addressed to make the really smart home; the domotics will provide energy saving, comfort, flexibility, safety
robot-brains is a repository for diy roboticists and experimenters. It's focused on Scheme.