oTasks is a multi-user tasks management system, featuring a recursive and distributed task tree, an open user management system (everybody can create an account), and email notifications. It can be used as trouble-ticket system.
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.