e3 is a full-screen, user-friendly text editor with an interface similar to that of either WordStar, Emacs, Pico, Nedit, or vi. It's heavily optimized for size and independent of libc or any other libraries, making it useful for mini-Linux distributions and rescue disks. The assembler version supports Linux, FreeBSD, OpenBSD, NetBSD, Win9x, QNX, Atheos, BeOS, ELKS, and DOS. There is also a separately distributed version written in C which supports some other Unix versions and CygWin. It is also possible to use regular expressions by using child processes like sed. e3 has a built in arithmetic calculator.
smake is a highly portable 'make' program that makes commands up to date based on rules in Makefiles and on the timestamps of the related files. It implements a complete superset of the features of the classical POSIX/Unix make program. It warns about typical misuse of dynamic macros that prevent portability of makefiles. Its automake features allow you to run scripts to automatically create rules for unknown platforms.
GImageView is a GTK+ based image viewer. It supports tabbed browsing, thumbnail table views, directory tree views, drag and drop, reading the thumbnail cache of other famous image viewers, and a flexible user interface. It also support movies using the Xine library and MPlayer, and supports images in compressed archive formats like tar.gz, zip, and lha.
Shilosh OS provides a secure and stable operating system based on a highly modified Linux kernel, with its own package system similar to BSD's "ports", BSD Init scripts. Compatible with x86 and Power PC, it is also 99% compatible with Windows 9x. It is easy to use and includes complete documentation in many languages.
h2incn tries to directly convert C/C++ headers to Nasm-style include files, and can be used in a makefile. It is useful if you want to use the same structures or external variable declarations in C and assembler code, and you don't want to use two separate files and update both each time you change something. It is written in a mix of C and C++ code. It currently works for simple files.
MakeNG is a system of makefiles that, in conjuncture with a patch to GNU Make, provides a concise, extensible, logically organized and easily modified system of makefiles to build any source tree or combination of components you can envision. MakeNG sports a fully documented extensible API on top of the classic GNU Make syntax (which is great for backwards compatibility).