Scripturian is a compact library that makes it very easy to integrate JVM languages (which support JSR-223). It lets you embed "scriptlets" into text documents, in the style of PHP, JSP, and ASP. It also allows boot strap JVM applications using any of the supported languages, which makes it easy to quickly configure and make changes in how your applications start up without re-compilation.
Khövsgöl is a minimal, highly configurable music player and browser. It can easily handle very large collections of music. It's designed for the GNOME desktop, but can run well in other environments. It works fine as a standalone player, but can also be used to remotely control music daemons such as MPD.
Succinct is a minimal templating engine designed for concurrency and efficiency. It has an especially abstract data model, allowing you to back your templates by fetching template data on-demand, during render-time, according to your own complex synchronization protocols. It comes with lots of tools to help you make your data "templatable."
Sincerity is a tool for installing and bootstrapping software stacks on top of the JVM. It makes these otherwise tedious tasks easy, simple, and fun. Your Sincerity containers are straightforward development playgrounds. Simply create a new container when you want to try out a new approach. Delete the directory when done, and it's as if nothing ever happened. Sincerity's growing ecology of plugins makes it especially easy to add powerful features to your product, such as centralized logging and robust daemons with surprisingly minimal fuss.