Black scalpel is an advanced graphical (Swing gui) security and analysis tool written in Java, C and Assembler (platform independent). Current stage is early alpha, many features are still missing. Use SVN!
embuild/atool is a mature embedded software development system including a unique make tool with auto-dependency generation, source and object version control, and some useful minor utilities. Support for gnu toolchain (C and assembler) included.
Compiler for java assembly to class file. This compiler contains dead code detection and allow creating method, field and constructor from a java assembly file
Xvid is an open source MPEG-4 video codec, written in C with assembler optmizations for quality and speed (including MMX, SSE, SSE2 and 3Dnow! code for i386 and AltiVec for PowerPC).
An implementation of the venerable MACRO assembler preprocessor from back in the mid 60's. It's interesting as a study of what was possible then, and how that
could be useful today.