Eventric - Eventric is an professional tour management solution.
Baïkal - Cal and CardDAV server
Peek Pro - Peek Pro is a fastest growing appointment scheduling software specially designed for tours and activity operators to help increase their booking reaching out to large numbers of potential customers, mostly tourists.
Radicale - The Radicale Project is a complete CalDAV (calendar) and CardDAV (contact) server solution.
Travolutionary - Travolutionary is an aggregation, reservation and distribution platform by Gimmonix, with access to hundreds of travel inventory providers across hotel, air, car and content.
DAViCal - DAViCal is a server for calendar sharing.