EyeOS is a free, cross-platform personal content manager system based upon the style of a desktop operating system. The base package includes the whole operating system structure and ten apps: a calendar, file manager, text editor, internal messenger, browser and calculator. EyeOS's is thought to provide a complete, scalable and free (GPL) organization and work system. Everyone can port an existing PHP app to EyeOS and create a meta-package. You can test it online here.