While the modern programming language Haxe is well-known in some circles, many developers have never heard of it. Yet since it first appeared in 2005, it's been battle-tested by its loyal---if rather quiet---following. It boasts a pragmatic and mature combination of features for development in business, gaming, and even academic contexts.
MonoDevelop enables developers to quickly write desktop and web applications on Linux, Windows and Mac OS X. It also makes it easy for developers to port .NET applications created with Visual Studio to Linux and Mac OS X maintaining a single code base for all platforms.
Processing is an open source programming language and environment for people who want to create images, animations, and interactions. Initially developed to serve as a software sketchbook and to teach fundamentals of computer programming within a visual context, Processing also has evolved into a tool for generating finished professional work. Today, there are tens of thousands of students, artists, designers, researchers, and hobbyists who use Processing for learning, prototyping, and production.
gtools is an extension for the mercurial version control system. The extension provides a graphical user interface for status, log, and commit operations.
Gobby is a free collaborative editor based on libobby, a library which provides synced document buffers. It supports multiple documents in one session and a multi-user chat. It runs on Microsoft Windows, Mac OS X, Linux and other Unix-like platforms.