A fast, unobtrusive and modern cross-platform GUI toolkit. Agar fully exploits hardware acceleration where available, but also supports simple frame-buffer interfaces. Agar is stand-alone and easily portable to new platforms and graphics systems.
ENG is a cross-platform event/object based SDL engine designed to manage many common application subsystems and to integrate the various input devices of handheld computers.
Smalltalk YX is an open source programming language. It's an implementation of the Smalltalk-80 standard.
X* is a powerful, extensible programming language that is using an Extensible Entity approach (A very enhanced OOP). I've been programming for the past 10 years with dozens of Programming Languages from different Paradigms... I wanted more.
XFX or XNA For XBOX is an open-source implementation of the XNA framework for the XBOX1 console. It is built on top of OpenXDK, the legal XBOX Development kit.
elastiC is a Very High Level Language (VHLL) with a C-like syntax. Dynamically typed, with fast Garbage Collection, supports functional programming and robust Object Orientation. Designed to be easily extended and embedded, it's portable and lightweight.