Berkeley DB XML is a native XML database engine for use within your product. Made available as a C++ library with language bindings for Java, Perl, Python, PHP, and Tcl, it integrates directly into your application (it is not a standalone database server). It provides XQuery access into a database of document containers. XML documents are stored and indexed in their native format using Berkeley DB as the transactional database engine.
BitNami RubyStack provides a fast, easy way to develop and deploy Ruby on Rails applications. It includes Ruby, Subversion, MySQL, SQLite, ImageMagick, and several Ruby Gems, and will optionally install Apache 2.2 with rewrite and proxy support. It supports Windows, Linux, and OS X, so you can share the same Rails environment on multiple platforms.
GraphicsMagick is a robust collection of tools and libraries which support reading, writing, and manipulating an image in over 90 major formats including popular formats like DPX, DICOM, BMP, GIF, JPEG, JPEG-2000, PDF, PNG, PNM, SVG, and TIFF. A high-quality 2D renderer is included, which provides a subset of SVG capabilities. C, C++, Perl, Tcl, and Ruby are supported. Originally based on ImageMagick, GraphicsMagick focuses on performance, minimizing bugs, and providing stable APIs and ABIs. It runs on all modern variants of Unix, Windows, and Mac OS X.
PhysicsFS is a library to provide abstract access to various archives. The programmer defines a "write directory" on the physical filesystem. No file writing done through the PhysicsFS API can leave that write directory, for security. For file reading, the programmer lists directories and archives that form a "search path". Once the search path is defined, it becomes a single, transparent, hierarchical filesystem. This makes for easy access to ZIP files in the same way as you access a file directly on the disk, and it makes it easy to ship a new archive that will override a previous archive on a per-file basis. Symbolic links can be disabled, for added safety. Finally, PhysicsFS gives you a platform- abstracted means to determine if CD-ROMs are available, the user's home directory, where in the real filesystem your program is running, etc.
Rant is a flexible build tool. The equivalent to a Makefile for make is the Rantfile, which is actually a valid Ruby script that is read in by the rant command. It currently features automated testing, packaging, and RDoc generation for Ruby applications and libraries, creation of gzipped tar and zip archives on all supported platforms without additional software, recognition of file changes based on MD5 checksums, dependency checking for C/C++ source files (makedepend is not required), and more. It can generate a script tailored to the needs of a specific project, which can be used instead of an Rant installation so that users aren't dependent on Rant.
BDDs [bry86] (or more precisely ROBDDs) are efficient data structures for representing a boolean formula. They are widely used in formal verification, in particular symbolic model-checking. Ruby- BDD, based on Buddy, provides access to BDDs from Ruby, a powerful and very easy to use object-oriented language. The purposes are quick prototyping and education.