The Marionette Collective (mcollective) is a framework to build server orchestration or parallel job execution systems. It uses modern technologies and concepts that make it ideal for large and cloud-based infrastructures. It's specifically geared towards systems administration tasks, but can be seen as a generic framework too.
PigeBox is a complete solution to record continuous (24/7/365) audio content. It provides a bootable GNU/Linux system with all required software components to achieve the storage, the recording, and the extraction of audio content. It has been designed to provide a "plug & record" solution for radio broadcasters.
rsync-mirror is used to backup local directories to another location on the local machine or to a remote machine. As the name suggests, it uses rsync for data transfer so it should be pretty efficient. It does not support any nifty backup features like incremental backups; all it does is mirror a directory to another location. To ease the task of creating backups, rsync-mirror takes care of managing the destination site of the backup. In case the target path needs to be mounted, rsync-mirror does so before backup and unmounts it afterwards.
BinBackup is a tool intended to efficiently back up a directory to a set of size-limited media like CD-Rs or DVD-Rs. It's goal is to distribute the contents of a directory to a set of media while using the space available on these media as best as possible, minimizing the number of media required for a backup. To do this, BinBackup uses a bin packing algorithm to decide how to partition the contents of a directory and where to put them.
XapianFu is a Ruby library for working with Xapian databases. It builds on the GPL licensed Xapian Ruby bindings, but provides an interface more in-line with "The Ruby Way"(tm) and is considerably easier to use. For example, you can work almost entirely with Hash objects, and XapianFu will handle converting the Hash keys into Xapian term prefixes when indexing and when parsing queries. It also handles storing and retrieving hash entries as Xapian::Document values. XapianFu basically gives you a persistent Hash with full text indexing (and ACID transactions).