GNU parallel is a shell tool for executing jobs in parallel locally or using remote computers. A job is typically a single command or a small script that has to be run for each of the lines in the input. The typical input is a list of files, a list of hosts, a list of users, a list of URLs, or a list of tables. If you use xargs today you will find GNU parallel very easy to use, as GNU parallel is written to have the same options as xargs. If you write loops in shell, you will find GNU parallel may be able to replace most of the loops and make them run faster by running several jobs in parallel. GNU parallel makes sure output from the commands is the same output as you would get had you run the commands sequentially. This makes it possible to use output from GNU parallel as input for other programs.
Multicrush is a wrapper around pngcrush that distributes the work of brute-force compressing a single image over several pngcrush processes. This gets you a slightly less than a linear speedup, caused by different compression methods having slightly different durations. For example, the author has measured a speedup of 1.92 on a 2-core Intel T5300, and 3.86 on a 4-core Intel Q6600. The only requirements are a copy of pngcrush and at least Python 2.4. If you have version 2.6 or higher, multicrush can automatically detect how many CPUs to use.
OpenMPF is a library for solving large, dense, multi-RHS linear systems. It is based on MPI/openMP parallelism, and relies on BLAS/LAPACK/MUMPS for the single node computations. It implements direct and iterative solvers, out-of-core matrices and vectors, and is easily accessible through a Python interface.
Moscrack is a WPA cracker for use on clusters. It supports MOSIX, SSH, and RSH connectivity and works by reading a word list from STDIN or a file, breaking it into chunks, and passing those chunks off to separate processes that run in parallel. The parallel processes are then executed on different nodes in your cluster. All results are checked and recorded on your master node. Logging and error handling are taken care of. It is capable of running reliably for long periods of time, without the risk of losing data or having to restart. Moscrack uses aircrack-ng by default. Pyrit for WPA cracking and Dehasher for Unix password hashes are supported via plugins.
phalanx computes a digest of many buffers simultaneously, and produces a combined hash of them all. It is an initiative to provide a fast, simple, and portable alternative method to compute a checksum in a parallel fashion. It has options for I/O buffer size, hash width, number of threads, and more. It can be run single-threadedly for performance comparisons. It can check files against previously-saved sums, like "MD5sum" does. It also has a "demo" mode, to ascertain accurate operation. It is intended to be useful on large files and multicore/multiprocessor/multithreaded environments.