SOGo - SOGo is groupware server with a focus on scalability and open standards.
Xola - Xola is an elegant and powerful online booking and distribution system. We help tour and activity providers reduce costs, grow revenue, and save time.
Baïkal - Cal and CardDAV server
Reservio - Reservio is a simple online booking and appointment scheduling application.
Xandikos - Lightweight CalDAV/CardDAV server on top of Git.
Eventric - Eventric is an professional tour management solution.