SchemDBG is a backend agnostic debugger frontend that focuses on debugging binaries without access to the source code.
Pint is a PIN tool that exposes the PIN API to lua scripts.
A new version of the old Corewars game. Containing a tournament system, visual debugger and assembler. Used for RWTH CTF 2011.
Azure is a small RISC bytecode VM with a powerfull macro assembler. Used for RWTH CTF 2012 (sources at github)
A LLVM based Brainfuck Compiler / JIT VM written in literate ruby. The code is hosted at github.