distributed.net is a loosely knit group of computer users from all of the world that is taking up challenges requiring lots of computing power (most notably the RC5, DES, and OGR cracking contests). It is simple to participate in the challenges by downloading and running their client software (which uses idle CPU time to complete its tasks).
GLE (Graphics Layout Engine) is a graphics scripting language designed for creating publication quality figures (e.g., a chart, plot, graph, or diagram). GLE supports various chart types (including function plot, histogram, bar chart, scatter plot, contour plot, color map, and surface plot) through a simple but flexible set of graphing commands. More complex output can be created by relying on GLE's scripting language, which is full featured with subroutines, variables, and logic control. GLE relies on LaTeX for text output and supports mathematical formulae in graphs and figures.
GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
KSEG is a program for exploring Euclidean geometry, similar to Geometer's Sketchpad. It features points, lines, transformations, measurements, calculations, simple editable recursive Constructions (similar to macros), adaptively sampled loci, and selection groups. Several languages are supported. KSEG is very fast, stable, and has an efficient and consistent UI. It uses Qt and does not require KDE.
LinAl was designed to bring together C++ and FORTRAN. At the same time LinAl is supposed to be easy to use, fast, and reasonably safe. The LinAl library is based on STL techniques and uses STL containers for the storage of matrix data and STL algorithms where feasible. Low level, algebraic operators, linear solvers, and eigenvalue solvers are implemented, based on calls to BLAS, LAPACK, and CGSOLX.
GTL can be seen as an extension of the Standard Template Library STL to graphs and fundamental graph algorithms. It is a platform independent and extendible C++ library, and is a useful aid to any software designer. It contains the classes needed to work with graphs, nodes, and edges, and some fundamental algorithms as building blocks for more complex graph algorithms. Customized algorithms can be developed by experienced programmers.
Yacas is a general purpose, easy to use Computer Algebra System (a CAS is a program that can be used to do symbolic manipulation of mathematical expressions). It is built on top of its own programming language designed for this purpose, in which new algorithms can easily be implemented. In addition, it comes with extensive documentation on the functionality implemented and methods used to implement them.
Botan is a crypto library written in C++. It provides a variety of cryptographic algorithms, including common ones such as AES, MD5, SHA, HMAC, RSA, Diffie-Hellman, DSA, and ECDSA, as well as many others that are more obscure or specialized. It also offers SSL/TLS (client and server), X.509v3 certificates and CRLs, and PKCS #10 certificate requests. A message processing system that uses a filter/pipeline metaphor allows for many common cryptographic tasks to be completed with just a few lines of code. Assembly and SIMD optimizations for common CPUs offers speedups for critical algorithms like AES and SHA-1.