The ATLAS (Automatically Tuned Linear Algebra Software) project is an ongoing research effort focusing on applying empirical techniques in order to provide portable performance. It provides C and Fortran77 interfaces to a portably efficient BLAS implementation, as well as a few routines from LAPACK.
SuperWaba is a VM for PDAs. Because of the way it was written, you can use Java to develop programs for it. It supports exceptions, threads, many user interface controls, double and long 64-bit types, grayscale, color, 3D controls, and JNI and Java libraries, among other features. The project has been superseded and replaced with TotalCross.
SmallBASIC is a free interpreter for BASIC, a simple computer language, targeting simplicity, mathematics, and graphics. Also, it has a powerfull string library, supports external C modules (shared libs), uses dynamic arrays (by default) and has no data types. Versions exists for Linux (or other Unix), PalmOS, DOS, Win32, VTOS (Helio), and Franklins (eBookman). It uses a lot of drivers, including svgalib, ncurses, and framebuffer.
Ficl (Forth inspired command language) is an ANS Forth interpreter written in C. Unlike traditional Forths, this interpreter is designed to be embedded into other systems as a command/macro/development prototype language. Ficl provides object extensions that can be used to wrap methods and structures of the host system without altering them.
The Helix Ribosome build system is a set of programs written in the Python programming language which provide a common interface to retrieving and building programs from source code stored in a CVS repository. The build system is made up of two basic subsystems. The first ("build") calculates the dependencies of a target, retrieves the source code, and runs commands to build that source code in the correct order. The second component ("Umake") is a cross-platform Makefile generator, which generates makefiles that work with MSVC, CodeWarrior, and typical Unix toolchains. Umake can be used independently from the build program.
f/Calc is a utility to calculate lens formulae for photographers so you can focus on the artistic bits rather than on the mathematics behind it all. f/Calc can do "f" number arithmetic, and can calculate depth of field, hyperfocal distance, the field of view of a lens, the angle of view of a lens, magnification, and how the focal length of the lens on the camera changes the way the spot metering function works. In addition to the Unix/Linux Tcl/Tk version, there are native Windows, Palm OS, and Macintosh versions as well.