Haiku (formerly known as OpenBeOS) is an operating system designed from the ground up for desktop computing. Inspired by the BeOS, it aims to provide users of all levels with a personal computing experience that is simple yet powerful, and free of any unnecessary complexities. It aims for source and binary compatibility with BeOS R5.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.