Binary Puzzle Solver in Ruby is an automated solver for Binary Puzzles (a kind of logic game) featured on http://www.binarypuzzle.com/. The solver contains an API and a commandline program and explains why it thinks the player should place a 0 or a 1 in the box. Although it contains only a subset of the moves the authors could think of and does not use backtracking, it was able to solve all the puzzles from binarypuzzle.com which the authors tried.
Tioga is a Ruby library for creating figures and plots with high quality text and graphics in PDF format. Text is processed directly by TeX (not an emulation), and the graphics covers a broad range of PDF features including images, curves, clipping, and transparency. Tioga is relatively easy to use, complete, and well documented.
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.
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.
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.