Shishi is an implementation of the kerberos v5 network authentication system.

SimGrid is a toolkit that provides core functionalities for the simulation of distributed applications in heterogeneous distributed environments. SimGrid can be used as a Grid simulator, a P2P simulator, a Cloud simulator, a MPI simulator, or a mix of all of them. The typical use-cases of SimGrid include heuristic evaluation, application prototyping, and real application development and tuning.

SINGULAR is a Computer Algebra System (CAS) for polynomial computations with emphasis on the special needs of commutative algebra, algebraic geometry, and singularity theory.

Qt is a cross-platform C++ application framework. Qt's primary feature is its rich set of widgets that provide standard GUI functionality.

SLEPc is a software library for the solution of large scale sparse eigenvalue problems on parallel computers. It is an extension of PETSc and can be used for either standard or generalized eigenproblems, with real or complex arithmetic. It can also be used for computing a partial SVD of a large, sparse, rectangular matrix.

Python, the high-level, interactive object oriented language, includes an extensive class library with lots of goodies for network programming, system administration, sounds and graphics.