6jack is a framework for testing, analyzing, and fuzzing network applications. 6jack runs a command, intercepts calls to common network-related system calls, and passes them through an external filter. A filter can be written in any language supporting the MessagePack serialization library. 6jack is especially useful for writing tests for clients and servers, debugging and reverse engineering protocols, sketching filtering proxies, and fuzzing.
AEditor is a programmer's editor for Windows, Unix, and Mac OS X that relies on the fox toolkit. It can do syntax coloring of Ruby and C++ files. It's easy to change the color theme. Most things are customizable. It is written in Ruby and is carefully unit-tested (it has 421 tests). It is written in only ~5500 lines of code, so it should be easy to grasp and extend.
AJAX Tree Control is a modified version of SilverStripe's tree control. It adds dynamic loading of child nodes via AJAX. The default implementation uses the prototype library to make dynamic requests, but this behavior can be overridden by setting functions on the global Tree object. There are a few demo Ruby on Rails applications included in the distribution that show how to use and customize the tree.
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.
Crackup is a pretty simple, pretty secure remote backup solution for folks who want to keep their data securely backed up but aren’t particularly concerned about bandwidth usage. Backups are compressed and (optionally) encrypted via GPG and can be transferred to the remote location over a variety of protocols, including FTP. Additional storage drivers can easily be written in Ruby.