JPPF makes it easy to parallelize computationally intensive tasks and execute them on a Grid.
dtools (Distributed tools) is a suite of programs that allows Unix commands to be run in parallel on a list of tagged hosts. It is based on Capistrano and Fabric, has a modular architecture and is easy to extend, and has full integration with SSH.
A markup language processor.
A game which looks like a Rubik's Cube, but is a slider, not a twister.