GLPI (Gestion Libre de Parc Informatique) is an information resource manager with an administration interface. You can use it to build a database with an inventory for your company (computers, software, printers, etc.). It has functions to make the daily life of the administrators easier, including a job/request tracking system with mail notification and methods to build a database with basic information about your network topology. It provides a precise inventory of all the technical resources (all their characteristics are stored in a database) and management and history of the maintenance actions and the bound procedures. It is dynamic and is directly connected to the users, who can post requests to the technicians.
ZABBIX is an enterprise-class distributed monitoring solution designed to monitor and track performance and availability of network servers, devices, and other IT resources. It supports distributed and Web-based monitoring, auto-discovery, real-time monitoring, SLA assurance, trending, and more.
Kronolith is the Horde calendar application. It provides a stable and featureful individual calendar system with integrated collaboration and scheduling features. It makes extensive use of the Horde Framework to provide integration with other applications. It implements a solid, stand-alone calendar system, allowing repeating events, all-day events, custom fields, keywords, shared calendars, iCalendar support, generation of free/busy information, and managing multiple users through Horde Authentication.