BitNami JRubyStack provides a fast, easy way to develop and deploy Ruby on Rails applications on a Java runtime using JRuby. It includes JRuby, Rails, Java, Tomcat, the GlassFish gem, MySQL, and Subversion. It supports Windows, Linux, and Mac OS X, so you can share the same Rails environment on multiple platforms.
Crabgrass is social networking, group collaboration, and network organizing Web application. It consists of a solid suite of group collaboration tools such as private wikis, task lists, a file repository, and decision making tools. Work is currently being done on a large user interface overhaul, better social networking tools, blogs, and event calendars, as well as better support for collaboration and decision making among independent groups.
The Marionette Collective (mcollective) is a framework to build server orchestration or parallel job execution systems. It uses modern technologies and concepts that make it ideal for large and cloud-based infrastructures. It's specifically geared towards systems administration tasks, but can be seen as a generic framework too.
Musicextras is a program for automatically retrieving extra information for songs. Currently it retrieves lyrics, album covers, artist images, and more. It was designed to make it easy to add other functionality. Information is obtained using plugins that parse Web page data. An example for having XMMS automatically load information for the currently playing MP3 is included.
Zbatery is an HTTP server for Rack applications on systems that either do not support fork(), or have no memory (nor need) to run the master/worker model. It is based on Rainbows! (which is based on Unicorn (which is based on Mongrel)) and inherits parts of each. Zbatery supports your choice of all the thread/fiber/event/actor-based concurrency models and Rack middleware that Rainbows! supports (or will ever support) in a single process. Zbatery will still exploit certain features of Unix for transparent upgrades, log reopening, and graceful stops, but does not rely on them for basic functionality.
Booh is a static Web-album generator. It takes one or several series of photos and videos, and automatically builds static Web pages to browse them, creating thumbnails, etc. It features automatic rotation of portrait images, support for videos, preloading, sub-albums support, themability, a powerful GUI for editing, and more. A companion program, booh-classifier, is a tool for batch deleting/copying/moving around images/videos, and is meant to be used prior to creating a Web-album (or in isolation).