Basecamp - A simple and elegant project management system.
Zimbra - Zimbra is trusted by over 500 million users to increase productivity with a complete set of collaboration tools while maintaining total control over security and privacy.
Keikai - Effortlessly Build Spreadsheet-driven Web Apps
Kolab Community - Kolab Groupware is a secure, scalable, reliable, flexible, full-featured collaboration suite.
SpreadsheetWEB - SpreadsheetWEB is a no-code platform that helps businesses translate their collective Microsoft Excel expertise into robust web applications with limited or no reliance on IT resources.
iRedMail - A fully fledged, free email server solution, an open source project (GPL v2).