GNU dico is a flexible dictionary server with a set of accompanying utilities. It supports a wide variety of dictionary database formats, ranging from the traditional "dict.org" databases up to Wikipedia format. Support for arbitrary new formats can be easily added using loadable modules. The dico library provides an API for writing new modules in C, Guile, or Python.
SafiServer is an engine that powers the applications called Saflets that control one or more Asterisk PBXs. These can be used for IVR applications such as information, account management, nearest dealer routing, and more. It also acts as an application repository for multi-developer environments.
Syncless is an experimental, lightweight, non-blocking (asynchronous) client and server socket network communication library implemented in Stackless Python 2.6. It contains an asynchronous DNS resolver (using dnspython) and an HTTP server capable of serving WSGI applications. It aims to be a coroutine-based alternative of event-driven networking engines (such as Twisted and FriendFeed's Tornado). It is already about that fast, but it has fewer features and is less stable now.
Graylog2 is an syslog implementation that stores logs in MongoDB. Messages are accepted via TCP or UDP. A Web interface allows you to view the log messages. It also implements GELF, the Graylog Extended Log Format, which is a simple JSON string that allows you to send long and structured syslog messages, which is very useful for customized application log monitoring.
UrBackup is an efficient client/server backup system for Linux and Windows. A client for Windows lets you backup open files and complete partition images. Incremental and full image backups are stored to disk in a efficient way with file level de-duplication on either Windows or Linux servers. An easy-to-use server Web interface lets you analyze storage usage, view logs, modify settings, and browse backups. Backup images can be restored using a prebuilt live Linux CD based on KNOPPIX.