openDesktop.org - The website openDesktop.
SourceForge - The Complete Open-Source and Business Software Platform.
OSOR - OSOR is the Open Source Observatory, a project to provide a framework for developing and executing autonomous observations.
Freecode - Freecode (formerly known as Freshmeat) is one of the legit open source development platforms that will be the key for developers and programmers to have a streamlined process via having enhanced collaboration and coding leverages.
ZenTao - ZenTao is an open source project management tool, supporting Scrum.
Eclipse - Eclipse is an open source community, whose projects are focused on building an open development platform comprised of extensible frameworks, tools and runtimes for building, deploying and managing software across the lifecycle.