A reverse engineering suite (decompiler, editor, debugger and more)
The slow descent into madness
A free C, C++ and Fortran IDE
Rapid applications development tool and libraries for FPC
an object-oriented language with late binding
ECLiPSe Constraint Logic Programming System
The world's first evidence-oriented programming language
Lua IDE/Debugger Plugin for IntelliJ IDEA
A native Windows port of the GNU Compiler Collection (GCC)
Homebrew toolchains for wii, gamecube, 3ds, ds, gba, gp32 and psp
grieferCode
An interpreter for the Lua language, written entirely in C#
C / C++ everything-memory debugger
Aspect Oriented Programming (AOP) for Erlang
Basic and Easy to use CSharp IDE with compiler.
Superseded by http://www.ti.com/tool/msp430-gcc-opensource
RapidDevelop is an IDE and Compiler for a new programming language!