PYX is a highly simplified XML derivative/substitute suitable for use in certain applications. In particular, PYX markup is easy to parse, and PYX documents are easily processed with simple tools. MyoPyx is a compact PYX document parser with a SAX-like API. Its small size makes it convenient for embedding in other applications who need some form of structured document markup, but don't need the weight of a full XML processor. It provides both Java and Ruby validating, streaming parsers.
Advertnet is tool for managing multiple networks of advertising boards, ready to work with Second Life. In Advertnet's model, the boards are attached to urban furnitures and can belong to different networks, thus forming ad campaigns. Differents types of objects can be attached to boards and networks: notecards, URLs, etc. Advertnet is composed of a Ruby on Rails application that can communicate with ad boards created in Second Life.
p4delta works with a project that is in the Perforce configuration management system. It lists the local files that have been added, changed, or deleted. Content differences are summarized, i.e., the number of lines of code that have been added, changed, and deleted. It can also add, edit, and remove the appropriate files to/from Perforce.
ProcPile is a pure Ruby distributed computing cluster environment. Its goal is to allow fast prototyping on smaller datasets, especially those where serialization and deserialization are minor expenses relative to the core processing task. Once the algorithms are settled, you should be able to scale out to full production usage. At that point, you can replace the core processes with Ruby modules written in C (or Inline::C), or move the design to a more "grown-up" clustering environment.