I recently contributed to the kickstarter project, Parallela which I would like to selfishly mention here. This is an interesting project that wants to develop highly cost effective small parallel machines. For example their smallest multi-process machine will cost $99 dollars and comprise of 16 processors controlled by a dual-core ARM A9 CPU, full spec is given below:
This machine is sort of like the multi-processor equivalent to the Raspberry Pi.. The next level board will have 64 processors for $200 which is incredible value. The catch is that the people behind the project must reach their goal.
From the kickstarter website, the project gives the following information:
The Parallella platform is based on the Epiphany multicore chips developed by Adapteva. The Epiphany chips consists of a scalable array of simple RISC processors programmable in C/C++ connected together with a fast on chip network within a single shared memory architecture.