AweMUD is a MUD server for use with fantasy-settings. Features include fully dynamic objects and characters, an advanced scripting system, and custom worlds. The engine will eventually have completely interactive rooms (items can be placed under benches, doors can be destroyed), complex magick, and interactive NPCs.
CVSsuck is a mirroring tool for CVS repositories. Unlike other tools such as CVSup or rsync, it uses cvs command to access the repository. So, it works well with remote repositories without a special server or shell account. However, it is inefficient because the CVS client/server protocol is not designed for mirroring.
GeoToad is a geocaching query tool to help speed up the boring part of geocaching: choosing the cache and collecting the data. It allows you to generate any kind of complex query you want, and the program will go and poll the Geocaching query, grab the data, and output it to any format you want. The Geocache info can be synced straight to your GPS, iPod, PDA, or cell phone in over 20 different formats.
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.