DokuWiki is a lightweight and highly versatile Open Source wiki software that works without a database.
EtherCalc is a web spreadsheet. Your data is saved on the web, and people can edit the same document at the same time. Everybody's changes are instantly reflected on all screens.
A real time collaborative drawing tool using nodejs, socket.io & paper.js
Etherpad is a highly customizable online editor that allows collaborative editing in real-time.
MediaWiki is a high-capacity, scalable software and a wiki implementation full of features.
MoinMoin is a high performance, easy to use and extensible WikiEngine, that can be used local without web server.
Efficiently plan, steer, and communicate within your projects. With open source and open mind.
Redmine is a web-based, flexible and extensible project management and bug-tracking tool.
Request Tracker is a ticket-tracking system used to coordinate tasks and manage requests among a community of users.
Free. Open Source. Powerful. Taiga is a project management platform that makes work truly enjoyable.